diff --git "a/Botany/beginners_botany_1921.md" "b/Botany/beginners_botany_1921.md" new file mode 100644--- /dev/null +++ "b/Botany/beginners_botany_1921.md" @@ -0,0 +1,5532 @@ +58 B 15 + +ONTARIO +HIGH SCHOOL +BEGINNERS' BOTANY + +AUTHORIZED BY +THE MINISTER OF EDUCATION +FOR ONTARIO + +PRICE 6 CENTS + +THE MACMILLAN CO. OF CANADA +LIMITED. + +511 B + +1921 +B1558 +Otc + + +EDUCATION DEPARTMENT +LIBRARY +ONTARIO. +OCT 24 1921 + + +D + +Digitized by the Internet Archive +in 2008 with funding from +Microsoft Corporation + +http://www.archive.org/details/beginnersbotany00baiuoft + +BEGINNERS' BOTANY + +The Macmillan logo +THE MACMILLAN COMPANY +NEW YORK • BOSTON • CHICAGO +SAN FRANCISCO +MACMILLAN & CO., LTD. +LONDON • BOMBAY • CALCUTTA +THE MACMILLAN CO OF CANADA, Ltd. +TORONTO + +[API_EMPTY_RESPONSE] + +BOUQUET OF BEARDED WHEAT + +BEGINNERS' BOTANY + +BY +L. H. BAILEY + +A coat of arms with two lions holding a shield, and a crown above. + +AUTHORIZED BY THE MINISTER OF EDUCATION +FOR ONTARIO + +TORONTO +THE MACMILLAN CO. OF CANADA, LIMITED +1921 + +38515 +COPYRIGHT 1921 +BY THE MACMILLAN CO. OF CANADA LTD. + +I + +PREFACE + +In all teaching of plants and animals to beginners, the plants themselves and the animals themselves should be made the theme, rather than any amount of definitions and of mere study in books. Books will be very useful in guiding the way, in arranging the subjects systematically, and in explaining obscure points; but if the pupil does not know the living and growing plants when he has completed his course in botany, he has not acquired very much that is worth the while. + +It is well to acquaint the beginner at first with the main features of the entire plant rather than with details of its parts. He should at once form a mental picture of what the plant is like, and of the uses to which it is adapted to the life that it leads. In this book, the pupil starts with the entire branch or the entire plant. It is sometimes said that the pupil cannot grasp the idea of struggle for existence until he knows the names and the uses of the different parts of the plant. This is an error, although well established in present-day methods of teaching. + +Another very important consideration is to adapt the statement of any fact to the understanding of a beginner. It is easy, for example, to fall into technicalities when discussing osmosis; but the minute explanations would mean nothing to the beginner and their use would tend to confuse the picture which it is necessary to leave in the pupil's mind. Even the use of technical forms of expression would probably not go far enough to satisfy the trained physiciat. + +V + +vi +PREFACE + +It is impossible ever to state the last thing about any proposition. All knowledge is relative. What is very elementary to one mind may be very technical and advanced to another. It is neither necessary nor desirable to safeguard statements to the beginner by such qualifications as will make them satisfactory to the critical expert in science. The teacher must understand that while accuracy is always essential, the degree of statement is equally important when teaching beginners. + +The value of biology study lies in the work with the actual objects. It is not possible to provide specimens for every part of the work, nor is it always desirable to do so; for the beginning pupil may not be able to interest himself in the objects, and he may become immersed in details before he has arrived at any general view or reason of the subject. Great care must be exercised that the pupil is not swamped. More book work or memory stuffing is useless, and it may dwarf or divert the sympathies of active young minds. + +The present tendency in secondary education is away from the formal technical completion of separate subjects and toward the developing of a workable training in the scientific relations between the pupil to his own life. In the natural science field, the tendency is to attach less importance to botany and zoology as such, and to lay greater stress on the processes and adaptations of life as expressed in plants and animals. Education that is not applicable, that does not put the pupil into touch with the living knowledge and the affairs of his time, may be of less educative value than the learning of a trade in a shop. We are beginning to learn that the ideals and the abilities should be developed out of the common surroundings and affairs + +PREFACE + +vii + +of life rather than imposed on the pupil as a matter of abstract unrelated theory. + +It is much better for the beginning pupil to acquire a real conception of a few central principles and points of view respecting common forms that will enable him to tie his knowledge together and organize it and apply it, than to familiarize himself with any number of mere facts about the lower forms of life which, at the best, he can know only indirectly and remotely. If the pupil wishes to go farther in later years, he may then take up special groups and phases. + +[API_EMPTY_RESPONSE] + +CONTENTS + +CHAPTER I. No Two Plants or Parts are Alike 1 +II. The Struggle to Live 4 +III. Survival of the Fit 7 +IV. Plant Societies 9 +V. The Plant Body 15 +VI. Seeds and Germination 20 +VII. The Root—the Forms of Roots 32 +VIII. The Root—Function and Structure 38 +IX. The Stem—Kinds and Forms—Pruning 49 +X. The Stem—Its General Structure 59 +XI. Leaves—Form and Position 73 +XII. Leaves—Structure and Anatomy 86 +XIII. Leaves—Function or Work 92 +XIV. Defendent Plants 106 +XV. Winter and Dormant Buds 111 +XVI. Bud Progagation 121 +XVII. How Plants Climb 129 +XVIII. The Flower—Its Parts and Forms 133 +XIX. The Flower—Fertilization and Pollination 144 +XX. Flower-clusters 155 +XXI. Fruits 163 +XXII. Dispersal of Seeds 172 +XXIII. Phenograms and Cryptograms 176 +XXIV. Studies in Cryptograms 182 +Index ix + +[API_EMPTY_RESPONSE] + +BEGINNERS' BOTANY + +CHAPTER I + +NO TWO PLANTS OR PARTS ARE ALIKE. + +Fig. 1. — No Two Branches Are Alike. (Henslow.) + +If one compares any two plants of the same kind ever so closely, it will be found that they differ from each other. The difference is apparent in size, form, colour, mode of branching, number of leaves, number of flowers, vigour, season of maturity, and the like; or, in other words, all plants and animals vary from an assumed or standard type. + +If one compares any two branches or twigs on a tree, it will be found that they differ in size, age, form, vigour, and in other ways (Fig. 2). + +If one compares any two leaves, it will be found that they are unlike in size, shape, colour, veining, hairiness, markings, cut of the margins, or other small features. In some cases (as in Fig. 2) the differences are so great as to be readily seen in a small black-and-white drawing. + +3 +1 + +2 + +BEGINNERS' BOTANY + +If the pupil extends his observation to animals, he will still find the same truth; for probably no two living objects are exact duplicates. If any person finds two objects that he thinks to be exactly alike, let him set to work to + + +A plant with small leaves and a few larger leaves. + + +Fig. 8. — No Two Leaves Are Alike. + +discover the differences, remembering that nothing in nature is so small or apparently trivial as to be overlooked. + +Variation, or differences between organs and also between organisms, is one of the most significant facts in nature. + +SUGGESTIONS.—The first fact that the pupil should acquire about plants is that no two are alike. The way to apprehend this great fact is to see a plant accurately and then to compare it with + +NO TWO PLANTS OR PARTS ARE ALIKE 3 + +another plant of the same species or kind. In order to direct and concentrate the observation, it is well to set a certain number of attributes or marks or qualities to be looked for. 1. Suppose any two or more plants to be so closely connected in their growing positions as to render it desirable to see whether the parts exactly agree. See that the observation is close and accurate. Allow no guesswork. Illustrate the pupil to measure with the eye, and make note of all observed. + +(1) Does it branch? How many secondary stems or "suckers" from one root? +(2) Shade or colour. +(3) Height of leaves. +(4) Arrangement of leaves on stem. +(5) Measure length and breadth of six main leaves. +(6) Number and position of eyes; colour of albs. +(7) Size and arrangement of buds on tips of branches. +(8) Stage of maturity or ripeness of plant. +(9) Has the plant grown symmetrically, or has it been crowded by other plants or been obliged to struggle for light or room? +(10) How does it grow? + +(11) Always make note of comparative vigour of the plants. + +NOTE TO TEACHER.--The teacher should always insist on per- +sonal work by the pupil. Every pupil should handle and study the object by himself. Books and pictures are merely guides and help; but if possible, study the plant or animal just where it grows naturally. + +Notebooks.--Institut that the pupils make full notes and preserve them carefully. This will aid in organizing the mental processes, and in insuring accuracy of observa- +tion and record. The pupil should draw what he sees, even though he is not expert with the pencil. The drawing should not be a copy of a book, but an attempt to depict entirely simply the object; it should be a means of self-expression. + +CHAPTER II + +THE STRUGGLE TO LIVE + +Every plant and animal is exposed to unfavourable conditions. It is obliged to contend with these conditions in order to live. + +No two plants or parts of plants are identically exposed to the conditions in which they live. The large branches + +A illustration of various fruits and vegetables, including apples, pears, grapes, and carrots. +**Fig. 3. — A BATTLE FOR LIFE.** + +In Fig. 1 probably had more room and a better exposure to light than the smaller ones. Probably no two of the leaves in Fig. 2 are equally exposed to light, or enjoy identical advantages in relation to the food that they receive from the tree. + +Examine any tree to determine under what advantages or disadvantages any of the limbs may live. Examine similarly the different plants in a garden row (Fig. 3); or the different bushes in a thicket; or the different trees in a wood. + +4 + +THE STRUGGLE TO LIVE + +The plant meets its conditions by succumbing to them (that is, by dying), or by adapting itself to them. + +The tree meets the cold by ceasing its active growth, hardening its tissues, dropping its leaves. Many her- +baceous or soft-stemmed plants meet the cold by dying to the ground and withdrawing all life into the root parts. +Some plants meet the cold by dying outright and provid- +ing abundance of seeds to perpetuate the kind next season. + +A tree with dense foliage on the left side and sparse foliage on the right side. +Fig. 4.—The Reach for Light of a Tree on the Edge of a Wood. + +Plants adapt themselves to light by growing toward it +(Fig. 4); or by hanging their leaves in such position that +they catch the light; or, in less sunny places, by expand- +ing their leaf surface, or by greatly lengthening their +stems so as to overtop their fellows, as do trees and vines. + +The adaptations of plants will afford a fertile field of +study as we proceed. + +6 +BEGINNERS' BOTANY + +Struggle for existence and adaptation to conditions are among the most significant facts in nature. + +The sum of all the conditions in which a plant or an ani- +mal is placed is called its environment, that is, its surround- +ings. The environment comprises the conditions of climate, +soil, moisture, exposure to light, relation to food supply, +contention with other plants or animals. The organism +adapts itself to its environment, or else it wakens or dies. +Every weak branch or plant has undergone some hardship that +was not wholly able to withstand. + +SUGGESTIONS.-The pupil should study any plant, or branch of +a plant, with reference to the position or condition under which it +grows, and compare one plant or branch with another. With animals, +it is necessary to consider their natural enemies, whether they be +to cause danger, or to protect itself. 2 A is well to begin with a +branch of a tree, as in Fig. 1. Note that no two parts are alike (Chap. +I). That note some are large and strong and that these stand far- +thest from the ground. Some are small and weak and are barely +able to live under the competition. Some have died. The pupil can +easily determine which of the dead branches perished first. He should +take note of the position or place of the branch on the tree, and deter- +mine whether it was near the top, middle, or bottom of the tree. He should +compare this with his own position in the room. He should observe +the centre of the tree top or toward the outside of it. Determine whether +an accident has overtaken any of the parts. 3 Let the pupil examine +the top of any thick old apple tree, to see whether there is any +branching out at all. If there is none, he may conclude that it is dead. If +the pupil has access to a forest, let him determine why there are no +branches on the trunks of the old trees. Examine a tree of the same +kind growing in an open field. 4 A rose of lettuce or other plants will grow in a bed of corn or potatoes. Any fine row or weedly place will also show it. Why does the farmer destroy the weeds among the corn or potatoes? How does +the florist reduce compost in order to get terms? What is the result? + +CHAPTER III + +THE SURVIVAL OF THE FIT + +The plants that most perfectly meet their conditions are able to persist. They perpetuate themselves. Their offspring are likely to inherit some of the attributes that enabled them successfully to meet the battle of life. The fit (those best adapted to their conditions) tend to survive. + +Adaptation to conditions depends on the fact of variation; that is, if plants were perfectly rigid or invariable (all exactly alike) they could not meet new conditions. Conditions are necessarily new for every organism. It is impossible to picture a perfectly inflexible and stable succession of plants or animals. + +Breeding - Man is able to modify plants and animals. All our common domestic animals are very unlike their original ancestors. So all our common and long-cultivated plants have varied from their ancestors. Even in some plants that have been in cultivation less than a century the change is marked; compare the common black-currant with its common wild ancestor, or the cultivated blackberry with the wild form. + +By choosing seeds from a plant that pleases him, the breeder may be able, under given conditions, to produce + +Fig. 5. Disembale and Undisembale Types of Cotton Plants. Why? + +7 + +8 + +BEGINNERS' BOTANY + +numbers of plants with more or less of the desired qualities; from the best of these, he may again choose; and so on until the race becomes greatly improved (Figs. 5, 6, 7). This process of continuously choosing the most suitable plants is known as selection. A somewhat similar process proceeds in wild nature, and it is then known as natural selection. + +—6. Every pure strain of a plant, whether it be a dextro- or a levo-rotatory one, will produce at least one simple experiment in selection. He may select the best plant of ears in the field, and also from the poorest plant,—having reference not so much to mere incidental size and vigour of the plants that put forth the ears, but to their general appearance. The ears may be saved and sown the next year. Every crop can no doubt be very greatly improved by a careful process of selection, and this is often done in practice. Crops are increased in yield or efficiency in three ways: better general care; catching the head in which they grow; attention to breeding. + +A diagram showing a plant with two different types of seeds. +Fig. 6. —Flax breeding. +A is a plant grown for seed production; +B is a plant grown for flax. + +A diagram showing a plant with two different types of seeds. +Fig. 7. —Dextro-rotating. +A, ears from heads bearing many heavy grains (after four years), average weight of such ears being 300 grains. +B, ears from heads bearing many light grains (after four years), average weight 100 grains. + +8 + +CHAPTER IV + +PLANT SOCIETIES + +In the long course of time in which plants have been accommodating themselves to the varying conditions in which they are obliged to grow, they have become adapted to every different environment. Certain plants, therefore, may live together or near each other, all enjoying the same general conditions and surroundings. These aggregations of plants that are adapted to similar general conditions are known as plant societies. + +Moisture and temperature are the leading factors in determining plant societies. The great geographical societies or aggregations of the plant world may conveniently be associated chiefly with the moisture supply, as: wet-region societies, comprising aquatic and bog vegetation (Fig. 8); arid-region societies, comprising desert and most sand-region vegetation; mid-region societies, comprising the mixed vegetation in intermediate regions (Fig. 9), this being the commonest type. Much of the characteristic scenery of any place is due to its plant societies. Arid-region plants usually have small and hard leaves, apparently preventing too rapid loss of water. Usually, also, they are characterized by stiff growth, hairy covering, spines, or a much-contrasted plant-body, and often by large underground organs for the storage of water. + +Plants can also be distinguished according to latitude and temperature. There are tropical societies, temperate-region societies, boreal or cold-region societies. + +9 + +10 +BEGINNERS' BOTANY + +With reference to altitude, societies might be classified as lowland (which are chiefly wet-region), intermediate (chiefly mid-region), subalpine or mid-mountain (which are chiefly boreal), alpine or high-mountain. + +The above classifications have reference chiefly to great geographical floras or societies. But there are societies within societies. There are small societies coming within the experience of every person who has ever seen plants growing in natural conditions. There are roadside, fence-row, lawn, thicket, pasture, dune, woods, cliff, barn-yard societies. Every different place has its characteristic vegetation. Notable smaller societies are 8 and 9. In the former is a water-lily society and a cat-tail society. In the latter there are grass and bush and woods societies. + +Some Details of Plant Societies. — Societies may be composed of scattered and intermingled plants, or of dense clumps or groups of plants. Dense clumps or groups are usually made up of one kind of plant, and they are then + +A wet-region society. +Fig. 8. — A WET-REGION SOCIETY. + +PLANT SOCIETIES II + +called colonies. Colonies of most plants are transient: after a short time other plants gain a foothold amongst them, and an intermingled society is the outcome. Marked exceptions to this are grass colonies and forest colonies, in which one kind of plant may hold its own for years and centuries. + +In a large newly cleared area, plants usually first establish themselves in dense colonies. Note the great patches + +A mid-region society. +Fig. 9.—A Mid-region Society. + +of nettles, jewel-weeds, smart-weeds, clot-burs, fire-weeds in recently cleared but neglected swales, also the fire-weeds in recently burned areas, the rank weeds in the neglected garden, and the ragweeds and May-weeds along the recently worked highway. The competition amongst themselves and with their neighbours finally breaks up the colonies, and a mixed and intermingled flora is generally the result. + +In many parts of the world the general tendency of vegetated areas is to run into forest. All plants rush for the + +12 +BEGGINNERS' BOTANY + +cleared area. Here and there bushes gain a foothold. +Young trees come up; in time these shade the bushes and gain the mastery. Sometimes the area grows to poplars or birches, and people wonder why the original forest trees do not return; but these forest trees may be growing unob- +served here and there in the tangle, and in the slow pro- +cesses of time the poplars perish—for they are short-lived +—and the original forest may be replaced. Whether one kind of forest or another returns will depend partly on the kinds that are most seedly in that variety of soil and which, +therefore, have sown themselves most profusely. Much +depends, also, on the kind of underground that first springs up, for some young trees can endure more or less shade than others. + +Some plants associate. They grow together. This is possible largely because they diverge or differ in charac- +ter. Plants associate in two ways: by growing side by side; by growing above or beneath. +In sparsely populated societies, plants may grow alongside each other. In most cases, however, +there is overgrowth and undergrowth: + +Overgrowth and Undergrowth in Three Series—trees, bushes, grass. + +one kind grows beneath another. Plants that have become adapted to shade are usually undergrowths. In a cat- +tail swamp, grasses and other narrow-leaved plants grow in the bottom, but they are usually unseen by the casual + +PLANT SOCIETIES 13 + +observer. Note the undergrowth in woods or under trees (Fig. 10). Observe that in pine and spruce forests there is almost no undergrowth, partly because there is very little light. + +On the same area the societies may differ at different times of the year. There are spring, summer, and fall soci- +eties. The knoll which is cloth with grass and strawberry- +s in June may be aglow with goldenrod in September. +If the barometer rises in May, and for these plants there are to be considered July and October, if in Septem- +ber, find the dead stalks of the flora of May. What suc- +ceeds the skunk cabbage, hepatica, trillium, phlox, violets, +buttercups of spring? What precedes the wild sunflowers, +ragweed, asters, and goldenrod of fall? + +The Landscape.—To a large extent the colour of the land- +scape is determined by the character of the plant societies. +Evergreen societies remain green, but the shade of green +varies from season to season; it is bright and soft in +spring, becomes dull in midsummer and fall, and assumes +a dull yellow-green or a black-green in winter. Deciduous +societies vary remarkably in colour—from the dull browns +and grays of winter to the brown greens and olive-greens +of spring, the staid greens of summer, and the brilliant +colours of autumn. + +The autumn colours are due to intermingling shades of +green, yellow, and red. The coloration varies with the kind +of plant, its species location, and the season. Even in the +same species or kind, individual plants differ in colour; and +this individuality usually distinguishes the plant year by +year. That is, an oak which is maroon red this autumn is +likely to exhibit that range of colour every year. The au- +tumn colour is associated with the natural maturity and +death of the leaf, but it is most brilliant in long and open + +14 + +**BEGINNERS' BOTANY** + +falls — largely because the foliage ripens more gradually and persists longer in such seasons. It is probable that the autumn tints are of no utility to the plant. **Autumn colours are not caused by frost.** Because of the long, dry falls and the great variety of plants, the autumnal colour of the American landscape is phenomenal. + +**Ecology.** — The study of the relationships of plants and animals to each other and to seasons and environments is known as ecology (still written ecology in the dictionaries). It considers the habits, habitats, and modes of life of living things—the places in which they grow, how they migrate or are disseminated, means of collecting food, their times and seasons of flowering, producing young, and the like. + +**Suggestions.** — One of the best of all subjects for school instruc- +tion in botany is the study of plant societies. It adds definiteness and zest to the study of plants. A society consists of one or two societies. Visit one day a swamp, another day a forest, another a pasture or meadow, another a roadside, another a weedly field, another a garden, another a orchard, another a meadow, another a swamp. Each pupil should be assigned a lot of ground—say 10 or 20 ft. +square—for special study. He should make a list showing (i) +how many kinds of plants he sees on his lot; (ii) what kind of each. The lists secured in different regions should be com- +pared. It does not matter greatly if the pupil does not know all the plants on his lot but he should know what he sees. It is a good plan for the pupil to make a dried specimen of each kind for reference. The +reasons for this are: (a) to discover why the plants grow next +each other and which are undergrowth and which overgrowth; and which are erect and which wide-spreading. **Challenge every plant society.** + +CHAPTER V + +THE PLANT BODY + +The Parts of a Plant. — Our familiar plants are made up of several distinct parts. The most prominent of these parts are root, stem, leaf, flower, fruit, and seed. Familiar plants differ wonderfully in size and shape,—from fragile mushrooms, delicate waterweeds and pond-scums, to floating leaves, soft grasses, coarse weeds, tall bushes, slender climbers, gigantic trees, and hanging moss. + +The Stem Part. — In most plants there is a main central part or shaft on which the other or secondary parts are borne. This main part is the plant axis. Above ground, in most plants, the main plant axis bears the branches, leaves, and flowers; below ground, it bears the roots. + +The rigid part of the plant, which persists over winter and which is left after leaves and flowers are fallen, is the framework of the plant. The framework is composed of both root and stem. When the plant is dead, the framework remains for a time, but it slowly decays. The dry winter stems of weeds are the framework, or skeleton of the plant (Figs. 11 and 12). The framework of trees is the most conspicuous part of the plant. + +The Root Part. — The root bears the stem at its apex, but otherwise it normally bears only root-branches. The stem bears leaves, flowers, and fruits. Those living surfaces of the plant which are most exposed to light are green or highly coloured. The root tends to grow downward, but the stem tends to grow upwards toward light. + +13 + +16 +BEGINNERS' BOTANY + +and air. The plant is anchored or fixed in the soil by the roots. Plants have been called "earth parasites." + +The Foliage Part. —The leaves precede the flowers in point of time or life of the plant. The flowers always precede the fruits and seeds. Many plants die when the seeds have matured. The whole mass of leaves of any plant or any branch is known as its foliage. +In some cases, as in crocuses, the flowers seem to precede the leaves; but the leaves that made the food for these flowers grew the preceding year. + +The Plant Generation. +—The course of a plant's life, with all the events through which the plant naturally passes, is known as the plant's life-history. +The life-history com- +braces various stages, +epochs, as dormant +seed, germination, growth, flowering, fruiting. Some plants run their course in a few weeks or months, and some live for centuries. + +The entire life-period of a plant is called a generation. +It is the whole period from birth to normal death, without reference to the various stages or events through which it passes. + +A generation begins with the young seed, not with germi- + +Fig. 11.—PLANT OF A WILD SUNFLOWER. +Fig. 12.—FRAMES WORK OF FIG. 11. + +17 + +THE PLANT BODY + +nation. It ends with death — that is, when no life is left in any part of the plant, and only the seed or spore remains to perpetuate the kind. In a bulbous plant, as a lily or an onion, the generation does not end until the bulb dies, even though the top is dead. + +When the generation is of only one season's duration, the plant is said to be annual. When it is of two seasons, it is biennial. Biennials usually bloom the second year. When of three or more seasons, the plant is perennial. Examples of annuials are pigweed, bean, pca, garden sunflower; of biennials, evening primrose, mullein, teasel; of perennials, dock, most meadow grasses, cat-tail, and all shrubs and trees. + +Duration of the Plant Body — Plant structures which are more or less soft and which die at the close of the season are said to be herbaceous, in contradistinction to being ligneous or woody. A plant which is herbaceous to the ground is called an herb; but an herb may have a woody or perennial root, in which case it is called an herbaceous perennial. Annual plants are classed as herbs. Examples of herbaceous perennials are buttercups, bled- ing heart, violet, waterlily, Bermuda grass, horse-radish, dock, dandelion, goldenrod, asparagus, rhubarb, many wild sunflowers (Figs. 11, 12). Many herbaceous perennials have short generations. They become weak with one or two seasons of flowering and gradually die out. Thus, red clover usually begins to fail after the second year. Gardeners know that the best bloom of hollyhock, harkspur, pink, and many other plants, is secured when the plants are only two or three years old. + +Herbaceous perennials which die away each season to bulbs or tubers, are sometimes called pseud-annuals (that + +C + +18 +BEGINNERS' BOTANY + +is, false annuals). Of such are lily, crocus, onion, potato, and bull nettle. + +True annuals reach old age the first year. Plants which are normally perennial may become annual in a shorter-season climate by being killed by frost, rather than by dying naturally at the end of a season of growth. They are cli-matic annuals. Such plants are called *plur-annuals* in the short-season region. Many tropical perennials are plur- + +A black and white illustration of a plant with long, thin leaves. +FIG. 13. -- A STRUGGLED PLANT. Dogwood odor. + +annuals when grown in the north, but they are treated as true annuals because they ripen sufficient of their crop the same season in which the seeds are sown to make them worth cultivating, as tomato, red pepper, castor bean, cotton. Name several vegetables that are planted in gardens with the expectation that they will bear till frost comes. + +Woody or ligninous plants usually live longer than herbs. Those that remain low and produce several or + +THE PLANT BODY + +19 + +many similar shoots from the base are called *shrub*, as lilac, rose, elder, osier (Fig. 13). Low and thick shrubs are *bushes*. Plants that produce one main trunk and a more or less elevated head are *trees* (Fig. 14). All shrubs and trees are perennial. + +Every plant makes an effort to propagate, or to perpetuate its kind; and, as far as we can see, the only end for which the plant itself lives. The seed or spore is the final product of the plant. + +**Suggestions.** — 8. The teacher may assign each pupil to one plant in the school yard, or field, or in a pot, and ask him to bring out the points in the lesson. 9. The teacher may put on the board the names of many common plants and ask the pupils to classify them under the following heads: *annuals* (aromatic annual), biennials, perennials, herbaceous perennials, ligneous perennials, herbs, bushes, trees. Every plant grown on the farm should be classified under these headings: *corn*, *potato*, *tomato*, *strawberry*, raspberry, currant, tobacco, alfalfa, flax, cruciferous crops, beans, cowpea, field bean, sweet potato, peanut, radish, sugar-cane, burley, cabbage, and others. Name all the kinds of trees you know. + +Fig. 14. — A Tree. The sweeping. + +CHAPTER VI + +SEEDS AND GERMINATION + +The seed contains a miniature plant, or embryo. The embryo usually has three parts that have received names: the stellet, or caudicle; the seed-leaf, or cotyledon (usually 1 or 2); the bud, or plumule, lying between or above the cotyledons. These parts are well seen in the common bean (Fig. 13), particularly when the seed has been soaked for a few hours. The two large cotyledons comprising half of the bean is shown at A. The caudicle is at O. The plumule is shown at A'. The cotyledons are attached to the caudicle at F'; this point may be taken as the first node or joint. + +The Number of Seed-leaves. — All plants having two seed-leaves belong to the group called dicotyledons. Such seeds in many cases split readily in halves, e.g., a bean. Some plants have only one seed-leaf in a seed. They form a group of plants called monocotyledons. Indian corn is an example of a plant with only one seed-leaf: a grain of corn does not split into halves as a bean does. Seeds of the pine family contain more than two cotyledons, but for our purposes they may be associated with the dicotyledons, although really forming a different group. + +These two groups—the dicotyledons and the monocotyledons—represent two great natural divisions of the vegetable kingdom. The dicotyledons contain the woody + +Fig. 15.—PARTS OF THE BEAN. +20 + +SEEDS AND GERMINATION 21 + +bark-bearing trees and bushes (except conifers), and most of the herbs of temperate climates except the grasses, sedges, rushes, lily tribes, and orchids. The flower-parts are usually in fives or multiples of five, the leaves mostly netted-veined, the bark or rind distinct, and the stem often bearing a pith at the centre. The monocotyledons usually have the flower-parts in threes or multiples of three, the leaves long and parallel-veined, the bark not separable, and the stem without a central pith. + +Every seed is provided with food to support the germinating plant. Commonly this food is starch. The food may be stored in the cotyledon, as in bean, pea, squash ; or outside the cotyledon, as in castor bean, pine, Indian corn. When the food is outside or around the embryo, it is surrounded by a protective coat. + +**Seed-coats; Markings on Seed.** —The embryo and endosperm are enclosed within a covering made of two or more layers and known as the seed-coats. +Over the point of the caulicle is a minute hole or a thin place in the coats known as the micropyyle. This is the point at which the pollen-tube entered the forming ovule and through which the caulicle breaks in germination. The micropyyle is shown at A in Fig. 16. +The scar where the seed broke from its funiculus (or stalk that attached it to its pod) is named the hilum. It occupies a third of the length of the bean in Fig. 16. The hilum and micropyyle are always present in seeds, but they are not always close together. In many cases it is difficult to identify the micropyyle in the dormant seed, but its location is at once shown by the protruding caulicle as germination begins. Opposite the micropyyle in the bean (at the other end of the hilum) is an elevation known as the raphe. + +Fig. 16.—Enter- +nal Parts of +Bean. + +22 +BEGINNERS' ROTARY + +This is formed by a union of the funiculus, or seed-stalk, with the seed-coats, and through it food was transferred for the development of the seed, but it is now functionless. +Seeds differ wonderfully in size, shape, colour, and other characteristics. They also vary in longevity. These characteristics are peculiar to the species or kind. Some seeds maintain life only a few weeks or even days, whereas others will "keep" for ten or twenty years. In special cases, seeds have retained vitality longer than this limit, but the stories that live seeds, several thousand years old, have been taken from the wrappings of mummies are unfounded. + +**Germination.** — The embryo is not dead; it is only dormant. When supplied with moisture, warmth, and oxygen (air), it awakens and grows; this growth is **germination**. The embryo lives for a time on the stored food, but gradually the plantlet secures a foothold in the soil and gathers food for itself. When the plantlet is finally able to shift its body freely, it is said to be **emerged**. + +**Early Stages of Seedling.** — The germinating seed first absorbs water, and swell. The starches gradually become soluble. The seed-coats are ruptured, the caudicle and plumule emerge. During this process the seed respires freely, throwing off carbon dioxide (CO₂). + +The caudicle usually elongates, and from its lower end roots are emitted. The elongating caudicle is known as the **hypocotyl** ("below the cotyledons"). That is, the hypocotyl is that part of the stem of the plantlet lying between the roots and the cotyledon. The general direction of the young hypocotyl, or emerging caudicle, is downwards. As soon as roots form, it becomes fixed and its subsequent growth tends to raise the cotyledons above the ground, as in the bean. When cotyledons rise into the + +SEEDS AND GERMINATION 23 + +air, germination is said to be epigaeal ("above the earth"). Bean and pumpkin are examples. When the hypocotyl does not elongate greatly under ground, the germination is hypogaeal ("be-neath the earth"). Pea and scarlet runner bean are examples (Fig. 48). When the germinating seed lics on a hard surface, as on closely compacted soil, the hypocotyl and rootlets may not be able to secure a foothold and they assume grotesque forms (Fig. 17). Try this with peas and beans. + +The first internode ("between nodes") above the cotyledons is the epicotyl. It elevates the plumule into the air, and the plumule-leaves expand into the first true leaves of the plant. These first true leaves, however, may be very unlike the later leaves in shape. + +Germination of Bean. - The common bean, as we have seen (Fig. 15), has cotyledons that occupy all the space inside the seed-coats. When the hypocotyl, or elongated caudicle, emerges, the plumule-leaves have begun to enlarge, and to unfold (Fig. 18). The hypocotyl elongates rapidly. One end of it is held by the roots. The other is held by the seed-coats in the soil. It therefore takes the form of a loop, and the central part of the loop "comes up" first (at Fig. 19). Presently the cotyledons come out of the seed-coats, + +Fig. 17.--PEA. Grotesque forms assumed when the roots cannot gain entrance to the soil. +Fig. 18.--COTYLEDONS OR GERMINATING BEAN SPREAD APART TO SHOW THE PLUMULE LEAVES AND CAULICLE AND PLEUCLE. + +24 + +**BEGINNERS' BOTANY** + +and the plant straightens and the cotyledons expand. These coty- +ledons, or "halves of the bean," persist for some time (a, Fig. +19). They often become green and probably perform some function of foliage. Because of its large size, the Lima bean shows all these parts well. + +**Germination of Castor Bean.** In the castor bean the hilum and micropyle are at the smaller end (Fig. 20). The bean "comes up" with a loop, which indicates that the hypocotyl greatly elongates. On examining germinat- +ing seed, however, it will be found that the cotyledons are contained inside a flshy body, or sac (a, Fig. 21). This sac is the endosperm. Against its inner surface the thin, veiny coty- +ledons are very closely pressed, ab- + + +A diagram showing the germination of a bean seed. + + +**Fig. 19.—GERMINATION OF BEAN.** + +**Fig. 20.—SPROUTING OF CASTOR BEAN.** + +**Fig. 21.—CASTOR BEAN. Endosperm at a; coty- +ledons at b.** + +The cotyledons increase in size as they reach the air (Fig. 23), and become func- +tional leaves. + +**Fig. 22.—GERMINATION OF CASTOR BEAN. Endosperm at a; coty- +ledons at b.** + +sorbing its substance (Fig. 22). The cotyledons increase in size as they reach the air (Fig. 23), and become func- +tional leaves. + +**Fig. 23.—GERMINATION OF CASTOR BEAN.** + +SEEDS AND GERMINATION 25 + +Germination of Monocotyledons.--Thus we have stud- +ied dicotyledonous seeds; we may now consider the mono- +cotyledonous group. Soak kernels of corn. Note that +the micropyle and hilum are at the smaller end (Fig. 24). +Make a longitudinal section through the narrow diameter; Fig. 25 shows it. The + + +A diagram showing the structure of a corn kernel. + + +Fig. 24.--SPROUTING +INDIAN CORN. +Section of a corn seed. +The embryo is at the micropyle. +The single cotyledon is at \(a\), the caulis at \(b\), the plumule at \(c\), and the coleoptile at \(d\). + +Fig. 25.--INDIAN CORN. +Longitudinal section of a corn kernel. +The embryo is at the micropyle. +The single cotyledon is at \(a\), the caulis at \(b\), the plumule at \(c\), and the coleoptile at \(d\). + +Fig. 26.--INDIAN CORN. +The emerging shoot is at the plumule, with a sheathing leaf (\(e\), Fig. 26). The root is emitted from the tip of the caulicle. The caulicle is held in a sheath (formed mostly from the seed-coats), and some of the roots escape through the upper end of this sheath (\(m\), Fig. 26). The epicotyl elongates, particularly if the seed is planted deep or if it is kept for a time confined. In Fig. 27 the epicotyl has elongated from \(s\) to \(p\). The true plumule-leaf is at \(o\), but other leaves grow from its sheath. In Fig. 28 the roots are seen emerging from the two ends of the caulicle. + + +A diagram showing the emergence of a shoot from an Indian corn seedling. + + + +A diagram showing the structure of an Indian corn seedling. + + +26 + +**BEGINNERS' BOTANY** + +sheath, $c$, $m$; the epicotyl has grown to $p$; the first phloem-leaf is at $e$. + +In studying corn or other fruits or seeds, the pupil should note how the seeds are arranged, as on the cob. Count the rows on a corn cob. Odd or even in number? Always the same number? The silk is the style: find where it was attached to the kernel. Did the ear have any coverings? Explain. Describe colours and markings of kernels of corn; and of peas, beans, castor bean. + +**Gymnosperms.** — The seeds in the pine cone, not being enclosed in a seed-vease, readily fall when the cone dries and the scales separate. Hence it is difficult to find cones with seeds in them after autumn has passed (Fig. 29). The cedar is also a gymnosperm. + +Remove a scale from a pine cone and draw it and the seeds as they lie in place on the upper side of the scale. + +Examine the seed, preferably with a magnifying glass. Is there a hilum? The micropyke is at the bottom or little end of the seed. Toss a seed upward into the air. Why does it fall so slowly? Can you explain the peculiar whirling motion by the shape of the wing? Repeat the ex + +Fig. 28.—GERMINATION IS COME. +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 +28 + +A, top of epicotyl; $x$, phloem-leaf; +$m$, roots; $e$, lower root. + +A, top of epicotyl; $x$, phloem-leaf; +$m$, roots; $e$, lower root. + +SEEDS AND GERMINATION 27 + +periment in the wind. Remove the wing from a seed and toss it and an uninjured seed into the air together. +What do you infer from these ex- +periments? + +**Suggestions.** — Few subjects con- +nected with the study of plant-life are so useful in schoolroom demonstrations as germination. The following experiment will show how the soil, plant the seeds, water them, and care for the plants. 10. Plant seeds in pots of sand or clay, which should not be very wide or long, and not over four inches deep. Holes may be bored in the sand to receive the seeds. 11. Plant a number of squash, bean, corn, pine, or other seeds about an inch deep in a box of sand or clay. The depth of planting should be two to four times the diameter of the seeds. Keep the sand or sawdust moist by watering it frequently. After several boxes, that the supply of supplies may be ample. Cigar boxes and earthenware pots are suitable individual pupils. It is well to begin the planting of seeds at least ten days in advance of their germination, and to make differ- +ent plantings at intervals. A day or two before the study is taken up, put seeds so that they will be ready to sprout; then has a series from sowling seeds to complete germination and all the steps can be made out. Dry seeds should be had for comparison with moist ones. A good deal of time will be required for every pupil, each ex- +periment may be assigned to a committee of two pupils to watch in the schoolroom. 12. Good seeds for study are those detailed in table 13. They include beans, peas, dill, radish, four o'clock, oats, wheat. It is best to use familiar seeds of farm and garden. Make drawings and notes of all the events taking place during this experiment, noting planting too deep and too shallow and different sides up. For +hypothetical germination, use the garden pea, scarlet-runner, or Dutch + +Cover of Hemlock (Asarum), White Pine, Pitch Pine. + +28 + +**BEGINNERS' BOTANY** + +case-knife bean, neuron, horse-chestnut. Squash seeds are excellent for germination studies, because the cotyledons become green and leafy and germination is rapid. Onion is excellent, except that it grows so fast that it is difficult to study its growth. The amount of germinating plantslet, it is well to provide a deeper box with a glass side against which the seeds are planted. 12. Observe the germination of any common seed about the house premises. When seeds, e.g., potatoes, are planted in the garden, they may be kept in boxes until they may be studied in boxes and along fences. 13. When studying germination the pupil should note the differences in shape and size between cotyledons and plumule leaves and between plumule leaves and the mature leaves of the plant. 14. In studying the germination described in the introductory experiments with bean, ear, the castor bean, and other seed for starch and protein tests. Test flour, oatmeal, rice, sunflower, flax, o'clock, various kinds of oats, and other seeds obtainable. Record your results by arranging the seeds in a cylinder or on a board. 15. Rate of growth of seedlings as affected by differences in temperature. Put two bottles of water into each. Cover each securely and set them in places having different temperatures that vary little. (A furnace room, a room with a stove, a room without stove but heated by sunshine, an unheated room near a window.) Place a thermometer in each bottle and read with the thermometer to find difference in temperature. The tumblers in warm places should be covered very tightly to prevent the germination from being retarded by drying out. Record number of seeds which have grown after 2 days, 3 days, 4 days, etc. + +16. Is air necessary for the germination and growth of seedlings? Place damp blanketing paper in the bottom of a bottle and fill it three-fourths full of soaked seeds, and close it tightly with a cork or rubber stopper. Keep this bottle in a warm place for one week. By having another bottle with all conditions the same except that it is covered loosely that air may have access to it, and set the bottles side by side (why keep the bottles together?). Record results as in the + +Fig. 20.--MUSKMELON SEEDLING, with the unlike seed-leaves and true leaves. + +BEEDS AND GEEMINATION 29 + +preceding experiment. 17. What is the nature of the gas given off by germinating seeds? Fill a tin box or large sealed bottle with clean, dry sand. Place a few seeds in the box and cover with true fruit juice. Fill one of them a third full of beans and keep them moist. Allow the other to remain dry. In a day or two insert a lighted splinter or taper into each. In the empty jar the taper burns; in contact oxygen is absorbed and carbon dioxide is given off by the burning. The air in the bottle may be tested for carbon dioxide by removing some of it with a rubber bulb attached to a glass tube (or a fountain pen filter) and bubbling it through limewater. The limewater will turn milky, showing perceivable rise in temperature is a mass of germinating seeds. This rise may be tested with a thermometer. 18. Interior of seeds. Seed needs for twenty-four hours and remove the coat. Distinctly the embryo is seen in the center of the seed, surrounded by a layer of food in the food in such? Some seeds of corn overwinter and recover the embryo, being careful not to injure the flaky cotyledon. Plant the incomplete and also some complete grain (in most cases this is not necessary). The embryo is usually killed by winter cold, but will destroy moulds and bacteria which might interfere with experiment.) Peas or beans may be sprouted on damp blotting paper; the cotyledons of one may be removed, and this with a normal seed equal quantity of water. The cotyledons are then placed in water in a jar so that the roots extend into the water. Their growth may be observed for several weeks. 21. Effect of darkness on seed and scotch moss A box may be placed mouth downward over a jar so that no light can reach it. Place a few seeds on the soil rest on half-inch boards to allow air to reach the seedlings. Note any effects on the seedlings of this cutting off of the light. An experiment similar to this may be made with mosses, e.g., a plank on green grass or moss, with a hole cut in it to change that takes place beneath it. 22. Scattering of pine. Plant pine seeds. Notice how they emerge. Do the cotyledons stay in the ground? How many leaves appear at once? What is the advantage of having leaves at once? What is the last part of the cotyledon to become free? Where is the growing point or phyllotaxis? How many leaves appear at once? Does the new pine tree grow on old wood or on wood formed from small branches? When do you see young trees on old grown cones on pine trees in winter? Are pine trees when grown on two-year-old wood? How long do they stay on a tree after the seeds have fallen out? What is the advantage of the seeds falling before they come? 23. Home experiments. If desired, nearly all of the fore- + +going experiments may be tried at home. The pupil can thus make the drawings for the notebook at home. A daily record of measurements of the change in size of the various parts of the seedling should also be made. + +**24. Seed-testing.** It is important that one know how to test seeds before planting them in the ground. A simple seed-tester may be made of two plates, one inverted over the other (Fig. 31). The lower plate is nearly filled with clean sand, and the upper plate is covered with a piece of cloth, on which the seeds are placed. Canton flannel is sometimes used in place of sand and blotting paper. The seeds are then covered with a second plate, and a piece of cloth, and water is applied until the sand and papers are saturated. Cover with the second plate. Set the plants where they will have plenty of light, and keep them in a temperature that the given seeds would prefer out of doors, or perhaps a slightly higher temperature. +Place 100 or more grains of clover, corn, wheat, oats, rice, rye, etc., in each plate, cover, and keep record of the number that sprout. The result will give a per centage measure of the ability of the seeds to grow. Note whether all the seeds sprout with equal vigour and rapidity. Most seeds will not germinate unless they are moistened with fresh sand and paper after each test, for some fungi are likely to breed in it. If canton flannel is used, it may be boiled. If possible, the seeds should not touch one another. + +**Note to Teacher.** With the start of germination, the pupil will need to begin directing. + +For directing, see a lens for the examination of the smaller parts of plants and seeds. It is best to have the lens mounted on a stand so that the pupil has both hands free for pulling the parts in pieces. An ordinary pocket lens only be mounted on a wire in a block as in Fig. A. A cork is slipped on the top of the wire to avoid injury to the face. The pupil should be permitted to direct his own experiments by using a needle as an ordinary needle in a pencil-like stick. Another convenient arrangement is shown in Fig. C. A small tin dish is used for the soil. Tolu oil or some other oil should be added. The dish is filled with water to make it heavy and firm. Insert a cork slipped on the stand so a cross wire is inserted holding on the end of a pencil's + +A diagram showing a simple seed-tester made from two plates, one inverted over the other. +**Fig. 31.—A HOME-MADE SEED-TESTER.** + +30 + +SEEDS AND GERMINATION + +31 + +glass. The lens can be moved up and down and sideways. This outfit can be made for about seventy-five cents. Fig. D shows a convenient hand-rotor or dissecting-stand to be used under this lens. It is made of wood, and is very light and easily handled. + +Various kinds of dissecting microscopes are on the market, and these are to be recommended when they can be afforded. + +A. DISSECTING STAND. + +B. DISSECTING NEEDLE, 1/2 inch size. + +C. DISSECTING GLASS. + +D. DISSECTING STAND FOR LENS. + +Instructions for the use of the compound microscope, with which some schools may be equipped, cannot be given in a brief space; the technique requires careful training. Such microscopes are not needed unless the pupil studies cells and tissues. + +CHAPTER VII + +THE ROOT--THE FORMS OF ROOTS + +The Root System.--The offices of the root are to hold the plant in place, and to gather food. Not all the food materials, however, are gathered by the roots. + +A diagram showing a taproot system of alfalfa. +Fig. 32.--TAP-ROOT SYSTEM OF ALFALFA. + +A diagram showing a tap-root of the dandelion. +Fig. 33.--TAP-ROOT OF THE DANDELION. + +The entire mass of roots of any plant is called its root system. The root system may be annual, biennial or perennial, herbaceous or woody, deep or shallow, large or small. + +Kinds of Roots.--A strong leading central root, which runs directly downwards, is a tap root. The tap-root forms 34 + +THE ROOT—THE FORMS OF ROOTS 33 + +an axis from which the side roots may branch. The side or spreading roots are usually smaller. Plants that have such a root system are said to be *top-rooted*. Examples are red clover, alfalfa, beet, turnip, radish, burdock, dandelion, hickory (Figs. 32, 33). + +A fibrous root system is one that is composed of many nearly equal slender branches. The greater number of plants have fibrous roots. Examples are many common grasses, wheat, oats, corn. The buttercup in Fig. 34 has a fibrous root system. Many trees have a strong taproot when very young, but after a while it ceases to extend strongly and the side roots develop finally the tap-root character disappears. + +Shape and Extent of the Root System.—The depth to which roots extend depends on the kind of plant, and the nature of the soil. Of most plants the roots extend far in all directions and lie comparatively near the surface. The roots usually radiate from a common point just beneath the surface of the ground. + +The roots grow here and there in search of food, often extending much farther in all directions than the spread of the top of the plant. Roots tend to spread farther in poor soil than in rich soil, for the same size of plant. The root has no such definite form as the stem has. Roots are usually very crooked, because they are constantly turned aside by obstacles. Examine roots in stony soil. + +A buttercup plant with fibrous roots. +FIG. 34.—A BUTTERCUP PLANT, with fibrous roots. + +34 +BEGINNERS' BOTANY + +The extent of root surface is usually very large, for the feeding roots are fine and very numerous. An ordinary plant of Indian corn may have a total length of root (measured as if the roots were placed end to end) of several hundred feet. + +The fine feeding roots are most abundant in the richest part of the soil. They are attracted by the food materials. Roots often will completely surround a bole or other morsel. When roots of trees are exposed, observe that most of them are horizontal and lie near the top of the ground. Some roots, as of willows, extend far in search of water. They often run into wells and drains, and into the margins of creeks and ponds. Grow plants in a long narrow box, in one end of which the soil is kept very dry and in the other moist; observe where the roots grow. + +**Buttresses.** — With the increase in diameter, the upper roots often protrude above the ground and become growing buttresses. These buttresses are usually largest in trees which always have been exposed to strong winds (Fig. 35). Because of growth and thickening, the roots elevate part of their diameter, and the washing away of the soil makes them to appear as if having risen out of the ground. + +The Blazing Base of a Field Pine. + +**Aerial Roots.** — Although roots usually grow underground, there are some that naturally grow above ground. These usually occur on climbing plants, the roots becoming supports or fulfilling the office of tendrils. These aerial roots usually turn away from the light, and therefore enter the + +THE ROOT—THE FORMS OF ROOTS + +35 + +crevices and dark places of the wall or tree over which the plant climbs. The trumpet creeper (Fig. 36), true or English ivy, and poison ivy climb by means of roots. + +Aerial root of an orchid. +**Fig. 37.—AERIAL ROOTS OF AN ORCHID.** + +In some plants all the roots are aerial; that is, the plant grows above ground, and the roots gather food from the air. Such plants usually grow on trees. They are known as epiphytes or air-plants. The most familiar examples are some of the tropical orchids which are grown in glass-houses (Fig. 37). Rootlike organs of dodder and other parasites are discussed in a future chapter. + +Aerial root of a trumpet creeper. +**Fig. 36.—AERIAL ROOTS OF TRUMPET CREEPER OR TONDA.** + +36 +BEGINNERS' BOTANY + +Some plants bear aerial roots, that may propagate the plant or may act as braces. They are often called prop-roots. +The roots of Indian corn are familiar (Fig. 38). Many ficus trees, as the banyan of India, send out roots from their branches; when these roots reach the ground they take hold and become great trunks, thus spreading the top of the parent tree over large areas. The mangrove tree of the tropics grows along seashores and sends down roots from the overhanging branches (and from the fruits) into the shallow water, and thereby gradually marches into the sea. The tangled roots behind catch-baskets in the soil is another example. + +Adventitious Roots.— Sometimes roots grow from the stem or other unusual places as the result of some accident to the plant, being located without known method or law. They are called adventitious (chance) roots. Cuttings of the stems of roses, figs, geraniums, and other plants, when planted, send out adventitious roots and form new plants. The ordinary roots, or soil roots, are of course not classified as adventitious roots. The adventitious roots arise occasionally but do not as a normal or regular course in the growth of the plant. + +No two roots are alike; that is, they vary among themselves as stems and leaves do. Each kind of plant has its + +Fig. 38.—Ficus Cornu, showing this brace root at ov. +38 + +THE ROOT--THE FORMS OF ROOTS + +37 + +even form or habit of root (Fig. 39). Carefully wash away the soil from the roots of any two related plants, as oats and wheat, and note the differences in size, depth, direction, mode of branching, number of fibres, colour, and other features. The character of the root system often governs the treatment that the farmer should give the soil in which the plant or crop grows. + +Roots differ not only in their form and habit, but also in colour of tissue, character of bark or rind, and other features. It is excellent practice to try to identify different plants by means of their roots. Let each pupil bring to school two plants with their roots very carefully dug up, as cotton, corn, potato, bean, wheat, rye, timothy, pumpkin, clover, sweet pea, raspberry, strawberry, or other common plants. + +**Root Systems of Weeds.** Some weeds are pestiferous because they seed abundantly, and others because their underground parts run deep or far and are persistent. Make out the root systems of the six worst weeds in your locality. + + +A: A root system with numerous fine branches. +B: A root system with fewer branches and larger diameter. + +FIG. 39--ROOTS OF BARLEY AT A AND CORN AT B. Carefully trace the differences. + +CHAPTER VIII + +THE ROOT. -FUNCTION AND STRUCTURE + +The function of roots is twofold, - to provide support or anchorage for the plant, and to collect and convey food materials. The first function is considered in Chapter VII; we may now give attention in more detail to the second. + +The feeding surface of the roots is near their ends. As the roots become old and hard, they serve only as channels through which water passes and as holdfasts or supports for the plant. The root-hold of plants is very strong. Slowly pull upwards on some plant, and note how firmly it is anchored in the soil. + +Roots have power to choose their food; that is, they do not absorb all substances with which they come in contact. They do not take up great quantities of useless or harmful materials, even though these materials may be abundant in the soil; but they may take up a greater quantity of some of the plant-foods than the plant can use to advantage. Plants respond very quickly to liberal feeding, - that is, to the application of plant-food to the soil (Fig 40). The poorer the soil, the more marked are the results, as a rule, of the application + +Fig 40.--Wheat growing under different conditions of TREATMENTS. Soil defi- cient in nitrogen; common nitrates applied to pot (3 on right). + +28 + +THE ROOT--FUNCTION AND STRUCTURE + +39 + +of fertilizers. Certain substances, as common salt, will kill the roots. + +**Roots absorb Substances only in Solution.** —Substances cannot be taken in solid particles. These materials are in solution in the soil water, and the roots themselves also have the power to dissolve the soil materials to some extent by means of substances that they excrete. The materials that come into the plant through the roots are water and mostly the mineral substances, as compounds of potassium, iron, phosphorus, calcium, magnesium, sulphur, and chlorine. These mineral substances compose the ash which the plant is burned. The carbon is derived from the air through the green parts. Oxygen is derived from the air and the soil water. + +**Nitrogen enters through the Roots.** + +—All plants must have nitrogen; yet, although about four-fifths of the air is nitrogen, plants are not able, so far as we know, to take it in through their leaves. +It enters through the roots in combination with other elements, chiefly in the form of nitrates (certain combinations with oxygen and a mineral base). The great family of leguminous plants, however (as peas, beans, cowpea, clover, alfalfa, vetch), use the nitrogen contained in the air in the soil. They are able to utilize it through the agency of nodules on their roots (Figs. 41, 42). These nodules contain bacteria, which appropriate the free or uncombined nitrogen and pass it on to the plant. The nitrogen + +Fig. 41.—NODULES ON ROOTS OF RED CLOVER. + +41 + +40 +BEGINNINGS BOTANY + +becomes incorporated in the plant tissue, so that these crops are high in their nitrogen content. Inasmuch as nitrogen in any form is expensive to purchase in fertilizers, the use of leguminous crops to plough under is a very important agricultural practice in preparing the land for other crops. In order that leguminous crops may acquire atmospheric nitrogen more freely and thereby thrive better, the land is sometimes sown or inoculated with the mold-forming bacteria. + +**Roots require moisture in soil water that is valuable to the plant is not the free water, but the thin film of moisture which adheres to a little particle of soil. The finer the soil, the greater the number of particles, and therefore the greater is the quantity of film moisture that it can hold. This moisture surrounding the grains may not be perceptible, yet the plant can use it. Root absorption may continue in a soil which seems to be dust dry. Soils that are very hard and + +A hand holding a small bowl filled with dark green seeds. +**Fig. 43** — **Two Kinds of Soil that have been Wet and then Dried.** The bottom soil above remains loose and capillary, while the top soil below has baked and cracked. + +A hand holding a small bowl filled with dark green seeds. +**Fig. 43** — **Two Kinds of Soil that have been Wet and then Dried.** The bottom soil above remains loose and capillary, while the top soil below has baked and cracked. + +THE ROOT—FUNCTION AND STRUCTURE 41 + +"baked" (Fig. 43) contain very little moisture or air, — not so much as similar soils that are granular or mellow. + +**Proper Temperature for Root Action.** — The root must be warm in order to perform its functions. Should the soil of fields or greenhouses be much colder than the air, the plant suffers. When in a warm atmosphere, or in a dry atmosphere, plants need to absorb much water from the soil, and the roots must be warm if the root-hairs are to supply the water as rapidly as it is needed. If the roots are chilled, the plant may wither or die. + +**Roots need Air.** — C.—n—on land that has been flooded by heavy rains, the roots become wet and turn yellow. Besides diluting plant-food, the water drives the air from the soil, and this suffocation of the roots is very soon apparent in the general ill health of the plant. Stirring or tilling the soil aerates it. Water plants and bog plants have adapted themselves to their particular conditions. They get their air either by special surface roots, or from the water through stems and leaves. + +**Rootlets.** — Roots divide into the thinnest and finest fibres: there are roots and there are rootlets. The smallest rootlets are so slender and delicate that they break off even when the plant is very carefully lifted from the soil. + +The rootlet, or fine divisions, are clothed with the root-hairs (Figs. 44, 45, 46). These root-hairs attach to the soil particles, and a great amount of soil is thus brought into actual contact with the plant. These are very delicate prolonged surface cells of the roots. They are borne for a short distance just back of the tip of the root. + +**Rootlet and root-hair differ.** The rootlet is a compact + +A small illustration showing a close-up view of a rootlet with fine hairs. +Fig. 46 — Rootlet +HEART OF THE RAISED + +42 +BEGINNERS' BOTANY + +cellular structure. The root-hairs is a delicate tubular cell (Fig. 45) within which is contained living matter (protoplast); and the protoplasmic lining membrane of the wall governs the entrance of water and substances in solution. Being long and tubular-like, these root-hairs are especially adapted for taking in the largest quantity of solutions; and they are the principal means by which plant-food is absorbed from the soil, although the surfaces of the rootlets themselves do their part. Water plants do not produce an abundant system of root-hairs, and such plants depend largely on their rootlets. + +The root-hairs are very small, often invisible. They, with the young roots, are usually broken off when the plant is pulled up. They are best seen when seeds are germinated between layers of dark blotting paper or funnel. On the young roots they will be seen as a mottle-like or gooseberry-like covering. Root-hairs soon die; they do not grow into roots. New ones form as the root grows. + +Osmosis.—The water with its nourishment goes through the thin walls of the root-hairs and rootlets by the process of osmosis. If there are two liquids of different density— + +Fig. 45.—Construction of Root. + +Fig. 46.—Root-hair, much enlarged, to contrast with the protoplast. Magnification 200 times; water-film on the particles at 10. + +THE ROOT—FUNCTION AND STRUCTURE + +43 + +on the inside and outside of an organic (either vegetable or animal) membrane, the liquids tend to mix through the membrane. The law of viscosity is that the most rapid flow is toward the denser solution. The protoplasmic lining of the root will act such a membrane. The soil water being a solute more than the sap in the roots, the fluid flows into the root. A strong fertilizer sometimes causes a plant to wither, or "burn it." Explain. + +Structure of Roots.—The root that grows from the lower end of the caudicle is the first or primary root. Secondary roots branch from the primary root. Branches of secondary roots are sometimes called tertiary roots. Do the secondary roots grow from the cortex, or from the central cylinder of the primary root? Trim or peel the cortex from a root and its branches and determine whether the branches still hold to the central cylinder of the main root. + +Internal Structure of Roots.—A section of a root shows that it consists of a central cylinder (see Fig. 45) surrounded by a layer. This layer is called the cortex. The outer layer of cells in the cortex is called the epidermis, and some of the cells of the epidermis are prolonged and form the delicate root-hairs. The cortex resembles the bark of the stem in its nature. The central cylinder contains many tube-like canals, or "vesicles" that convey water and food (Fig. 45). Cut a sweet potato across (also a radish and a turnip) and distinguish the central cylinder, epidermis, and phloem. Notice the hard cap on the tip of roots. Roots differ from stems in having no real pith. + +Microscopic Structure of Roots.—Examine at any end of any young root or shoot the cells are found to differ somewhat one another more or less, according to the distance from the point. This differentiation takes place in the region just back of the growing point. To study growing points, use + +44 +BEGINNERS' BOTANY + +the hypocotyl of Indian corn which has grown about one-half inch. Make a longitudinal section. Note these points (Fig. 47): (a) the tapering root-cap beyond the growing point; (b) the blunt end of the root proper and the rectangular shape of the cells found there; (c) the group of cells in the middle of the first layers beneath the root-cap; — this group is the growing point; (d) study the slight differences in the tissues a short distance back of the growing point. +There are four regions: the central cylinder, $d$, made up of several rows of cells in the outer layers; the endodermis, ($e$) composed of a single layer on each side which separates the central cylinder from the bark; the cortex, or inner bark, ($c$) of several layers outside the endodermis; and the epidermis, or outer layer of bark on the outer edges ($d$). Make a drawing of the section. If a series of the cross-sections of the hypocotyl should be made and studied by the pupil beginning near the growing point and going upward, it would be found that these four tissues become more distinctly marked, for at the tip the tissues have not yet assumed their characteristic form. The central cylinder contains the ducts and vessels which convey the sap. + +The Root-Cells. The four forms of the root-cap shown in the microscopic section drawn in Fig. 47. Growing cells, and especially those which are forming tissue by subdividing, are very delicate and are easily injured. The + +Fig. 47.—Growing Point OF Root OF INDIAN CORN. + +$d$, $e$, cells which will form the epidermis; $c$, cortex, or inner bark; $e$, endodermis, $e$, epidermis, or outer layer of bark on the outer edges ($d$). + +THE ROOT—FUNCTION AND STRUCTURE + +45 + +cells forming the root-cap are older and tougher and are suited for pushing aside the soil that the root may penetrate it. + +**Region of most Rapid Growth.** —The roots of a seedling bean may be marked at equal distances by waterproof ink or by bits of black thread tied moderately tight. The seedling is then replanted and left undisturbed for two days. When it is dug up, the region of rapid growth in the root can be determined. Give a reason why a root cannot elongate throughout its length, whether there is anything to prevent a young root from doing so. + +In Fig. 48 is shown a germinating scarlet runner bean with a short root upon which are marks made with waterproof ink; and the same root (Fig. 49) is shown after it has grown longer. Which part of it did not lengthen at all? Which part lengthened slightly? Where is the region of most rapid growth? + +**Geotropism.** —Roots turn toward the earth, even if the seed is planted with the micropyple up. This phenomenon is called **posi- tive geotropism.** Stems grow away from the earth. This is **negative geotropism.** + +Fig. 48.—The Marking of the Stem and Root. +Fig. 49.—The Result. + +46 +BEGINNERS' BOTANY + +SUGGESTIONS (Chaps. VII and VIII).—25. Tests for food. Examine a number of roots, including several fibrous roots, for the presence of starch. The starch may be detected by the following test. 26. Study of root-hairs. Carefully examine radish, turnip, cabbage, or other seed, so that no delicate parts of the root will be injured. For this purpose, cut off a piece of root about an inch long and a folk of thick cloth or of blotting paper, being careful to keep them moist and warm. In a few days the seed has germinated, and the root has grown out into a shoot. At this time, if the root is examined at a distance of about a quarter of an inch behind the tip, the root is covered with minute hairs (Fig. 44). They are actually hairs; that is, roots have hair-like structures on their surface. These hairs are so delicate that they can be removed by dipping one of the plants in water, and when removed the hairs are not to be seen. The water mutes them together along the root and they are no longer evident. Root-hairs are usually distributed over the whole surface of the root, but this is done ever so carefully. They cling to the minute particles of soil (Fig. 46). The hairs show best against a dark background. + +27. How to make a plant grow in sand. Observe how the root-hairs cling to the grains. Observe how they are flattened when they come in contact with grains of sand. 28. Root hairs on a plant growing in water. + +The pupil should also study the root hold. + +Let him take a small bulb and pull it up a plant. If a plant grows alongside a fence or some other rigid object, he may test, by cutting a string to see if the root holds by curving it around the string or by pulling on it until it breaks. + +Will a stake of similar size to the plant grow in sand? Will a stake deeper in the ground have such firm hold on loose earth? + +What holds the ball of earth in Fig. 50? + +29. How to make a plant grow strong on firm-packed earth in a pot; cover the bulb nearly to the top with loose earth; place in a cool cellar; after some days + +Fig. 50.—THE GRAPE OF A PLANT ON THE PARTI- CLES OF EARTH. A grass plant potted in a glass. + +THE ROOT—FUNCTION AND STRUCTURE + +or weeks, note that the bulb has been raised out of the earth by the force of gravity. All roots creep up on account of this as they grow. +Explain. 30. Response of roots and stems to the force of gravity, or gravitropism. Plant a fast-growing seedling in a pot so that the plumbine extends through the drain hole (Fig. 51). The stem will grow upwards, but the root will grow downwards (in the usual position). Or use a pot in which a plant is already growing, cover with cloth or wire gauze to prevent the roots from growing outwards. Place the plant in an inverted position (Fig. 51). Notice the behaviour of the stem, and after a few days remove the cloth or gauze. What do you observe? If a pot is laid on one side, and changed every two days and laid on its opposite side, the effect on the roots would be similar to that shown in Fig. 51. If a root is planted wrong end up, what is the result? +Try it with pieces of horse-radish root. 31. By placing a plant in an inverted position, the effect of gravity may be neutralized. 32. Region of root most sensitive to gravity. Lay on its side a pot containing a growing plant, and place it in a room where the earth surrounding the roots. Which turned downward most decidedly, the tip of root or the upper part? 33. Soil texture. Carefully turn up soil in a rich garden or field so that you have uncovered banks at large as a hen's egg. Then break these open carefully with the fingers and determine whether there are traces or remains of roots (Fig. 52). Are there any channels, holes, or channels made by roots? Are the roots still alive? How long are they living? 36. Compare: -a) other hump from a pile b) when plants have been grown, how many differ- ence in texture? 37. Grind up this clay lump very finely and put it in a saucer, cover with water, and set in the sun. After a time it will have the appearance shown in the lower saucer in Fig. 43. Compare this with the appearance of young plants grown best, even if the plant-food were the same in both? Why? 38. To test the effect of moisture on the plant, let a plant in a pot or box dry. + +Fig. 51.—Plant growth in Inverted Pot. +Fig. 52.—Holes in Soil made by Roots, now decayed. Shown in half. + +48 + +BEGINNERS' BOTANY + +out till it wils; then add water and note the rapidity with which it recovers. Vary the experiment in quantity of water applied. Does the plant call for water sooner when it stands in a sunny win- +dow than when it stands in a dark corner? Does it require a potted plant above the rim of the pot in a pile of water and let it remain there. What is the consequence? Why? 40. To test +the effect of different temperatures on the growth of ice water, and another in a dish of warm water, and keep them in a warm room. In a short time notice how still and vigorous is the +plant in each case. Observe also whether the leaves show signs of wilting. 41. The process of exosmose. Chip away the shell from the large end of an egg so as to expose the uninjured membrane beneath. With a sharp knife, cut off a piece of the shell about one-eighth inch long, and place it in a glass tube. Add to this a little washing- +was, chewing-gum, or paste, stick a quill about three inches long to +the smaller end of the egg. After the tube is in place, run a hot +water bath over the egg for several minutes, or use +a short glass tube, first scraping the shell thin with a knife and +then boring through it with the tube. Now set the egg upon the mouth of a pickle jar nearly full of water, so that the large end will be below the surface. Keep the jar in a warm place for several hours, observe the tube on top of the egg to see whether the water has forced its way into the egg and increased its volume so that pressure is exerted against the shell. If this does not take place at hand, see whether the contents are forced through the hole which has been made in the small end of the egg. Explain how the law of osmosis applies to this experiment. If no pressure is sustained only the membrane, would water rise into it? If there were no water in the bottle, would the egg-white pass down into the bot- +tle? If so, why? If not, why not? The egg-shell should +make marks with waterproof ink (as Higin's ink or indelible +marking ink) on any soft growing roots. Place seeds of bean, +radish, lettuce, etc., in a dish of water for two days and change the cloth. +Keep them damp and warm. When stem and root have grown +an inch and a half long each, with waterproof ink mark spaces +exactly one-quarter inch apart (Figs. 45, 46). Keep the plants until +roots have grown beyond these marks. Then remove all but some +or all of the marks are more than one-quarter inch apart; on the +root, the marks have not separated. The root has grown beyond +the last mark. + +A diagram showing a seedling with roots growing out from it. + +CHAPTER IX + +THE STEM—KINDS AND FORMS; PRUNING + +The Stem System.—The stem of a plant is the part that bears the buds, leaves, flowers, and fruits. Its office is to hold these parts up to the light and air; and through its tissues the various food-materials and the life-giving fluids are distributed to the growing and working parts. + +The entire mass or fabric of stems of any plant is called its stem system. It comprises the trunk, branches, and twigs, but not the stalks of leaves and flowers that die and fall away. The stem system may be herbaceous or woody, annual biennial or perennial; and it may assume many sizes and shapes. + +Stems are of Many Forms.—The general way in which a plant grows is called its habit. The habit is the appearance or general form. Its habit may be open or loose, dense, straight, crooked, compact, straggling, climbing, erect, weak, strong, and the like. The roots and the leaves are the important functional or working parts; the stem merely connects them, and its form is exceedingly variable. + +Kinds of Stems.—The stem may be so short as to be scarcely distinguishable. In such cases the crown of the plant—that part just at the surface of the ground—bears the leaves and the flowers; but this crown is really a very short stem. The dandelion, Fig. 33, is an example. Such plants are often said to be stemless; however, in order to distinguish them from plants that have long or conspicu- E 49 + +50 +BEGINNERS' BOTANY + +nous stems. These so-called stemless plants die to the ground every year. +Stems are erect when they grow straight up (Figs. 53, 54). They are trailing when they run along on the ground, + +Fig. 53.—Strict Simple Stem of Mullen. +Fig. 54.—Strict Upright Stem of Narrow-leaved Dock. + +as melon, wild morning-glory (Fig. 55). They are creeping when they run on the ground and take root at places, + +Fig. 55.—Trailing Stem of Wild Morning Glory (Clematis arvensis). + +as the strawberry. They are decumbent when they lie over to the ground. They are ascending when they lie mostly or in part on the ground but stand more or less upright at their ends; example, a tomato. They are + +THE STEMS—KINDS AND FORMS; PRUNING 51 + +climbing when they cling to other objects for support (Figs. 36, 36). + +Trees in which the main trunk or the "leader" continues to grow from its tip are said to be **excurrent** in growth. The branches are borne along the sides of the trunk, as in common pines (Fig. 57) and spruces. Excurrent means running out or running up. + +Trees in which the main trunk does not continue are said to be **deliquescent**. The branches arise from one common point or from each other. The stem is lost in the branches. The apple tree, plum (Fig. 58), maple, elm, oak, China tree, are familiar examples. Deliquescent means dissolving or melting away. + +Each kind of plant has its own peculiar habit or direction of growth. Spruces always grow to a single stem or trunk, pear + +Fig. 36.—A Climbing Plant. +**Fig. 36.—CLIMBING PLANT.** + +Fig. 37.—Excurrent Trunk. A pine. +**Fig. 37.—EXCURRENT TRUNK. A pine.** + +Fig. 38.—Incurrent Trunk of Plum Tree. +**Fig. 38.—INCURRENT TRUNK OF PLUM TREE.** + +52 +BEGINNERS' BOTANY + +trees are always deliquescent, morning-glories are always trailing or climbing, strawberries are always creeping. +We do not know why each plant has its own habit, but the habit is in some way associated with the plant's genealogy or with the way in which it has been obliged to live. +The stem may be simple or branched. A simple stem usually grows from the terminal bud, and side branches either do not start, or, if they start, they soon perish. Mollineux (Fig. 53) are usually simple. So are palms. +Branched stems may be of very different habits and shapes. Some stem systems are narrow and erect; these are said to be strict (Fig. 54). Others are diffuse, open, brachy, twiggy. + +Nodes and Internodes.—The parts of the stem at which buds grow are called nodes or joints and the spaces between the buds are internodes. The stem at nodes is usually enlarged, and the pith is usually interrupted. The distance between the nodes is influenced by the vigour of the plant; how? + +A hand-drawn illustration of a plant with leaves and stems. + +FIG. 59.—RHIZOME OR ROOTSTOCK. + +Stems vs. Roots.—Roots sometimes grow above ground (Chap. VII); so also, stems sometimes grow underground, and they are then known as subterranean stems, rhizomes or rootstocks (Fig. 59). +Stems normally bear leaves and buds, and thereby are they distinguished from roots; usually, also, they contain a pith. The leaves, however, may be reduced to mere scales, and the buds beneath them may be scarcely visible, + +THE STEMS—KINDS AND FORMS; PRUNING + +Thus the "eyes" on a white potato are cavities with a bud or bud at the bottom (Fig. 60). Sweet potatoes have no evident "eyes" when first dug, (but they may develop adventitious buds before the next growing-season). The white potato is a stem ; the sweet potato is probably a root. + +How Stems elongate. — Roots elongate by growing near the tip. Stems con- gate by growing more or less through- out the young or soft part or "between joints" (Figs. 48, 49). But any part of the stem soon reaches a limit beyond which it cannot grow, or it becomes fixed, and the new parts beyond elongate until they, too, become rigid. When a part of the stem once becomes fixed or hard, it never increases in length : that is, the trunk or woody parts never grow longer or higher; branches do not become farther apart or higher from the ground. + +Stems are modified in form by the particular or incidental conditions under which they grow. The struggle for light is the chief factor in determining the shape and the direc- tion of any limb (Chap. 11). This is well illustrated in any tree or bush that grows against a building or on the mar- gin of a forest (Fig. 4). In a very dense thicket the innermost trees shoot up over the others or they perish. Examining any stem and endeavour to determine why it took its particular form. + +The stem is cylindrical, the outer part being bark and the inner part being wood or woody tissue. In the dicoty- leonous plants, the bark is usually easily separated from the remainder of the cylinder at some time of the year ; in monocotyledonous plants the bark is not freely grown in thickness takes place inside the covering and not on the very + +Fig. 60.—SPROUTS ARISING FROM THE BUDS OR EYES OF A POTATO. +53 + +54 +BEGINNERS' BOTANY + +outside of the plant cylinder. It is evident, then, that the covering of bark must expand in order to allow of the expansion of the woody cylinder within it. The tissues, therefore, must be under constant pressure or tension. It has been determined that the pressure within a growing trunk is often as much as fifty pounds to the square inch. The lower part of the limb in Fig. 61 shows that the outer layers of bark (which are long since dead, and serve only as protective tissue) have reached the limit of their expanding capacity and have begun to split. The pupil will now be interested in the bark on the body of an old elm tree (Fig. 62); and he should be able to suggest one reason why some remain cylindrical, and why the old bark becomes marked with furrows, scars, and places. + +Many of these plants increase in diameter by the addition of an annual layer or "ring" on the outside of the woody cylinder, underneath the bark. The monocotyledonous plants comprise very few trees and shrubs in temperate climates (the palms, yuccas, and other tree-like plants are of this class), and they do not increase greatly in diameter and they rarely branch to any extent. + +**Bark-bound Trees.**—If, for any reason, the bark should become so dense and strong that the trunk cannot expand, the tree is said to be "bark-bound." Such condition is not rare in ornamental trees than have been neglected. When good tillage is given to such trees, they + +Fig. 61.—CRACKING OF BARK FROM AN OLD ELM TRUNK. + +Fig. 62.—PIECE OF BARK FROM AN OLD ELM TRUNK. + +THE STEMS—KINDS AND FORMS; PRUNING + +may not be able to overcome the rigidity of the old bark, and, therefore, do not respond to the treatment. Sometimes the parts with thinner bark may outgrow in diameter the trunk or the old branches below them. The remedy is to release the tension. This may be done either by softening the bark (by washes of soap or lye), or by separating it. The latter is done by slitting the bark-bound part (in spring), thrusting the point of a knife through the bark to the wood, and then drawing the blade down the entire length of the bark-bound part. The slit is scarcely discernible at first, but it opens with the growth of the tree, filling up with new tissue beneath. Let the pupil consider the ridges which he now and then finds on trees, and determine whether they have any significance—whether the tree has ever been injured or injuried by natural agencies. + +The Tissue covers the Wounds and "heals" them. +This is seen in Fig. 63, in which a ring of tissue rolls out over the wound. This ring of healing tissue forms most rapidly and uniformly when the wound is smooth and regular. Observe the healing on broken and splintered limbs; also the difference in rapidity of healing between wounds on strong and weak limbs. There is a difference in the rapidity of the healing process in different kinds of trees. Compare the apple tree and the peach. This tissue may in + +Fig. 63.—Proper Cutting of a Branch. The wound will soon be healed. +55 + +56 +BEGINNERS' BOTANY + +turn become bark-bound, and the healing may stop. On large wounds it progresses more rapidly the first few years than it does later. This roll or ring of the bark is called a callus. + +The callus grows from the living tissue of the stem just about the wound. It cannot cover long dead stubs or very rough broken branches (Fig. 64). Therefore, in pruning the branches should be cut close to the trunk and made even and smooth; all long stubs must be avoided. The seat of the wound should be close to the living part of the trunk, for the stub of the limb that is severed has no further power in itself of making healing tissue. The end of the remaining stub is merely covered over by the callus, and usually remains a dead piece of wood sealed inside the trunk (Fig. 65). + +Wounds do not heal over speedily, germs and fungi obtain foothold in the dying wood and rot sets in. Hollow trees are those in which the decay-fungi have progressed into the inner wood of the trunk; they have been infected (Fig. 66). + +Large wounds should be protected with a covering of paint, melted wax, or other adhesive and lasting material, + +Fig. 64.—Eucalyptus fronding. + +Fig. 65.—Knot in a Hemlock tree. + +THE STEMS—KINDS AND FORMS; PRUNING + +to keep out the germs, and fungi. +A covering of sheet iron or tin may keep out the rain, but it will not exclude the germs of decay; in fact, it may provide the very moist conditions that such germs need for their growth. Deep holes in trees should be treated by having all the decayed parts removed down to the clean wood, the surfaces painted or otherwise sterilized, and the hole filled with wax or cement. + +**Fig. 66.—A Root Hole,** and the beginning of a hollow trunk. + +Stems and roots are living, and they should not be wounded or mutilated unnecessarily. Horses should never be hitched to trees. Supervision should be exercised over persons who run telephone, telegraph, and electric light wires, to see that they do not mutilate trees. Electric light wires and tele- lley wires, when carelessly strung or improperly installed, may kill trees. + +**Suggestions.** — *Forms of stems.* + +43. Are the trunks of trees ever per- fectly cylindrical? If not, what may cause the irregularities? Do trunkwood rotting and decay occur more frequently than they used to? + +44. Sit a rapidly growing limb, in spring, with a knife blade, and watch the result during the summer months. What causes the wood to swell? Note especially the same ring at different places in the circumference. Cross-sections of + +**Fig. 67.—ELM TREE KILLED BY A DIRECT CURRENT FROM AN ELECTRIC RAILROAD TOWER.** + +A cross-sectional view of an elm tree trunk showing signs of damage caused by a direct current from an electric railroad tower. + +horizontal branches are interesting in this connection. 46. Note the enlargement at the base of a branch, and determine whether this enlargement occurs more frequently on the upper or lower parts than on upper or lower parts. Why does this bud-like development? Does it serve as a brace to the limb, and is it developed as the result of constant strain? 47. Strength of stems. The pupil should observe the fact that the stems of wonderful plants are constructed proportionate height, diameter, and weight of a grass stem with those of the bottom of the lowest leaf. Which is the strongest? Which has the greatest height? Which will withstand the most wind? Note that the grass stem will regain its position even if its top is bent to the ground. Note how plants are weighted down after a heavy rain by their own weight. Observe how a corn-stalk and observe how the joints are tied together and braced with fibres. Are there similar fibres in stems of pigweed, cotton, sunflower, hollyhock? + +Potato plant. +FIG. 68.—POTATO. What are roots, and what stems? Has the plant more than one kind of stem? more than two kinds? Explain. + +BEGINNERS' BOTANY + +CHAPTER X + +THE STEM--ITS GENERAL STRUCTURE + +There are two main types of stem structure in flowering plants, the differences being based on the arrangement of bundles or strands of tissue. These types are *endogenous* and *exogenous* (page 20). It will require patient laboratory work to understand what these types and structures are. + +*Endogenous*, or *Monocotyledonous* Stems. — Examples of endogenous stems are all the grasses, cane-brake, sugar-cane, smilax or green-brier, palma, banana, canna, balm-boo, lilies, yucca, asparagus, all the cereal grains. For our study, a cornstalk may be used as a type. + +A piece of corn-stalk, either green or dead, should be in the hand of each pupil while studying this lesson. Fig. 69 will also be of use. Is there a swelling at the nodes? Which part of the internode comes nearest to being perfectly round? There is a grooved channel running along one side of the internode: how is it placed with reference to the leaf? with reference to the groove in the internode below it? What do you find in each groove at its lower end? (In a dried stalk only traces of this are usually seen.) Does any bud on a cornstalk besides the one at + +Cross-section of corn-stalk showing vascular bundles. Slightly enlarged. + +59 + +60 +BEGINNINGS' BOTANY + +the top ever develop? Where do suckers come from? +Where does the ear grow? + +Cut a cross-section of the stalk between the nodes (Fig. +69). Does it have a distinct bark? The interior consists of soft "pith" and tough woody parts. The wood is found in strands or fibres. Which is more abundant? Do the fibres have any definite arrangement? Which strands are largest? Smallest? The firm smooth rind (which cannot properly be called a bark) consists of small wood strands packed closely together. Grass stems are hollow cylinders, and the constable, because of the lightness of its contents, is also practically a cylinder. Compare this kind of ad- +minimally and with providing a strong support to leaves and fruit. This is in accordance with the well-known law that a hollow cylinder is much stronger than a solid cylinder of the same weight of material. + +Cut a thin slice of the inner soft part and hold it up to the light. Can you make out a number of tiny compartments or cells? These cells consist of a tissue called **paren- +chyma**, the tissue from which young all the other tissues arise and differentiate. The numerous walls of these cells may serve to brace the outer wall of the cylinder, but their chief function in the young stalk is to give origin to other cells. When alive they are filled with cell sap and protoplasm. + +Trace the woody strands through the nodes. +Do they ascend vertically? Do they curve towards the mind at certain places? Compare with the strands shown in Fig. 78. The woody strands consist chiefly of tough fibrous cells thus giving rigidity. + + +A diagram showing the structure of a grass stem, highlighting the hollow cylinder and the fibrous strands within it. + + +FIG. 70. — DIA- +GRAM SHOW- +ING THE CON- +STRUCTION OF +FIBRO-VAECI- +LAR BARK AND +THE FIBERS IN +MONOCOTY- +LEONOUS +LEAVES. + + +THE STEM--ITS GENERAL STRUCTURE 61 + +and strength to the plant, and of long tubular interrupted canals that serve to convey sap upward from the root and to convey food downward from the leaves to the stem and the roots. + +Monocotyledons, as shown by fossils, existed before dicotyledons appeared, and it is thought that the latter were developed from ancestors of the former. It will be interesting to trace the relationship in stem structure. It will first be necessary to learn something of wood structure in the stem of monocotyledons. + +Wood Strands in Monocotyledons and Dicotyledons.--Each wood strand (or fibro-vascular bundle) consists of two parts--the bast and the wood proper. The wood is on the side of the strand towards the centre of the stem and contains large tubular canals that take the watery sap upward from the roots. The bast is on the side toward the bark, and contains fine tubes through which diffuses the dense sap containing digested food from the leaves. In the root (Fig. 71) the bast and the wood are separate, so that there are two kinds of strands. + +In monocotyledons, as already said, the strands (or bundles) are arranged in the stem with no definite arrangement (Figs. 75, 73). In dicotyledons the strands, or bundles, are arranged in a + + +A diagram showing different types of wood strands in a plant. + + +**FIG. 72.--DIAGRAM OF DIFFERENT TYPES OF STRANDS OR FIBRO-VASCULAR BUNDLES IN A PLANT.** +72 + +(a) Bast strand (b) Wood strand (c) Bast strand (d) Wood strand (e) Bast strand (f) Wood strand (g) Bast strand (h) Wood strand (i) Bast strand (j) Wood strand (k) Bast strand (l) Wood strand (m) Bast strand (n) Wood strand (o) Bast strand (p) Wood strand (q) Bast strand (r) Wood strand (s) Bast strand (t) Wood strand (u) Bast strand (v) Wood strand (w) Bast strand (x) Wood strand (y) Bast strand (z) Wood strand. + + +**FIG. 73.--PART OF CROSS-SECTION OF ROOT-STOCK OF ASPARAGUS, SHOWING A FEW FIBRO-VASCULAR BUNDLES IN THE STEM.** + +62 + +Dicotyledonous stem of one year at left with five bundles, and a two-year stem at right, e, the phloem; f, the wood part; g, the bast part; h, a one-year growth. + +**Fig. 73. — The natatory stem of the **Bundes** or **Serans**, in monochlamydeous plants. At a, and the bundle in a circle in the middle of the stem, the multiplication continues, in tough plants only the bundles touch (Fig. 74, right). The inner parts thus form a ring of wood and the outer parts form the inner bark or bast. A new ring of wood or bast is formed on stems of dicotyledons each year, and the age of a cut stem is easily determined. + +When cross-sections of monocotyledonous and dicotyledonous bundles are examined under the microscope, it is readily seen + +**Fig. 74. — The vascular bundle of Indian corn, much magnified.** + +62 + +THE STEM—ITS GENERAL STRUCTURE + +63 + +why dicotyledonous bundles form rings of wood and monocotyledonous cannot (Figs. 75 and 76). The dicotyledonous bundles (Fig. 76) has, running across it, a layer of brick-shaped cells called **cambium**, which cells are a specialized form of the parenchyma cells and retain the power of + +A diagram showing the structure of a stem with different types of cells. + +**Fig. 76.—THE DICOTYLEDONOUS BUNDLE OR WOOD-STEAD.** Upper figure shows the cambium, $d$, ductus, $x$, root of four years' growth; $z$, end of second year's growth; base part of leaf and wood part at right. Lower figure (from Wetmore), wood-often $q$; phloem, $p$; xylem, $x$; fundamental tissue or parenchyma, $a$; host, $h$; host parenchyma, $a'$; sieve-cubes. + +Growing and multiplying. The bundles containing cambium are called open bundles. There is no cambium in monocotyledonous bundles (Fig. 75) and the bundles are called closed bundles. Monocotyledonous stems soon cease to grow in diameter. The stem of a palm tree is almost + +64 + +**BEGINNERS' BOTANY** + +as large at the top as at the base. As dicotyledonous plants grow, the stems become thicker each year, for the delicate active cambium layer forms new cells from early spring until midsummer or autumn, adding to the wood within and to the bark without. As the growth in spring is very rapid, the first wood-cells formed are much larger than the last wood-cells formed by the slow growth of the + + +A cross-sectional view of a white pine stem, 5 years old. The outermost layer is bark. + + +late season, and the spring wood is less dense and of a lighter colour than the summer wood; hence the time between two years' growth is really made out (Figs. 77 and 78). Because of the rapid growth of the cambium in spring and its consequent soft walls and fluid contents, the bark of trees "peels" readily at that season. + +**Medullary Rays — The first year's growth in dicotyledons forms a woody ring which almost encloses the pith, and this is left as a small cylinder which does not grow...** + +THE STEM—ITS GENERAL STRUCTURE + +65 + +larger, even if the tree should live a century. It is not quite enclosed, however, for the narrow layers of soft cells separating the branches remain between them (Fig. 78), forming radiating lines called medullary rays or pith rays. + +The Several Plant Cells and their Vision.—In the wood there are some parenchyma cells that have thin walls still, but have lost the power of vision. They are now storage cells. There are also wood fibres which are thick-walled and rigid (Fig. 76), and serve to support the sap-cannals (tracheids) that are formed by the end walls of upright rows of cells; the canals pass from the roots to the twigs and even to ribs of the leaves and serve to transport the root water. They are recognized (Fig. 79) by the peculiar thickening of the wall on the inner surface of the tube, occurring in the form of spirals. Sometimes the whole wall is thickened except in spots called pits (Fig. 76). These thin spots (Fig. 80) allow the sap to pass to other cells or to neighbouring vessels. + +The cambium, as we have seen, consists of cells whose function is growth. These + +A diagram showing a longitudinal section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +A diagram showing a cross-section of a stem with various parts labeled. +r + +cells are thin-walled and filled with protoplasm. During the growing season they are continually adding to the wood within and the bark without; hence the layer moves outward as it deposits the new woody layer within. + +The bark consists of inner or fibrous bark or new bark (these fibres in flax become linen), the green or middle bark which functions somewhat as the leaves, and the corky or outer bark. The common word "bark" is seen, therefore, not to represent a homogeneous or simple structure, but rather a collection of several kinds of tissue, all separating from each other like the cambium. The new bark contains (1) the sieve-tubes (Fig. 81) which transport the sap containing organic substances, as sugar and proteins, from the leaves to the parts needing it (Fig. 76). These tubes have been formed like the wood vessels, but they have sieve-plates to allow the dense organic-laden sap to pass with sufficient readiness for purposes of rapid distribution. (2) There are also thick-walled bast fibres (Fig. 82) in the bast that serve for support. (3) There is also some parenchyma in the new bark; it is now in part a strong tissue. + +Fig. 81.--Sieve-tubes. +66 + +Fig. 82.--Thick-walled Bast Cells. + +THE STEM--ITS GENERAL STRUCTURE 67 + +times the walls of parenchyma cells in the cortex thicken at the corners and form brace cells (Fig. 83) (collenchyma) for support; sometimes the whole wall is thickened, forming grit cells or stone cells (Fig. 84; examples in tough parts of pear, or in stone of fruits). Some parts serve for secretions (milk, rosin, etc.) and are called latex tubes. + +**The outer bark** of old shoots consists of corky cells that protect from mechanical injury, and that contain a fatty substance (suberin) impermeable to water and of service to keep its moisture. There is sometimes a cork cambium (or phloem) which produces new cork cells by division and keeps them from splitting, thus increasing its power to protect. + +**Transport of the "sap."** We shall soon learn that the common word "sap" does not represent a single or simple substance. We may roughly distinguish two kinds of more or less fluid contents: (1) the root water, sometimes called mineral sap, that is taken in by the root, containing its freight of such inorganic substances as potassium, calcium, iron, and the rest; this root water rises, we have found, in the wood vessels, --that is, in the young or "sapwood" (p. 60); (2) the elaborated or organized materials passing back and forth, especially from the leaves, to build up tissues in all parts of the plant, some of it going down to the roots and root-hairs; this organic material is transported, as we have learned, in the sieve-tubes of the inner bark, --that is, in the "inner bark." Removing the bark from a trunk in + +Fig. 83.--COLLENCHYMA IN WILD JEWISH PEAR (PYRUS TOOTH-ME-NOT [sic. PATENS].) +Fig. 84.--GRIT CELLS. + +68 + +BEGINNERS' BOTANY + +a girdle will not stop the upward rise of the root water so long as the wood remains alive; but it will stop the passage of the elaborated or food-storied materials to parts below and thus starve those parts; and if the girdle does not heal over by the deposit of new bark, the tree will in time starve to death. It will now be seen that the common practice of placing wires or hoops about trunks to hold them in position or to prevent branches from falling is irrational, because such wires interpose barriers over which the fluids cannot pass; in time, as the trunk increases in diameter, the wire girdles the tree. It is much better to bolt the parts together by rods extending through the branches (Fig. 15). These should be stout and tight in their binding. Why? + +Wood.--The main stem or trunk, and sometimes the larger branches, are the sources of lumber and tim- +ber. Different kinds of wood have value for their special qualities. The business of raising wood, for all purposes, is known as forestry. The forest is to be considered as a crop, and the crop must be harvested, as much as corn or rice is harvested. Man is often able to grow a more pro- +ductive forest than nature does. + +Resistance to decay gives value to wood used for shingles (cypress, heart of yellow pine) and for fence posts (mul- +berry, cedar, post oak, bois d'arc, mequite). + +Hardness and strength are qualities of great value in building. Live oak is used in ships. Red oak, rock maple, + +Fig. 15.--THE WRONG WAY TO BRACE A TREE. (See Fig. 12.) +fig. 15.--THE WRONG WAY TO BRACE A TREE. (See Fig. 12.) + +THE STEM--ITS GENERAL STRUCTURE + +69 + +and yellow pine are used for floors. The best flooring is sawn with the straight edges of the annual rings upward; tangential sawn flooring may splinter. Chuteau is common in some parts of the country, being used for ceiling and inexpensive finishing and furniture. Lenoir and bois d'arc (orange) are used for hubs of wheels; bois d'arc makes a remarkably durable pavement for streets. Ebony is a tropical wood used for flutes, black piano keys, and fancy articles. Ash is straight and elastic; it is used for handles for light implements. Hickory is very strong as well as elastic, and is superior to ash for handles, spokes, and other uses where strength is wanted. Hickory is never sawn into lumber, but is split or turned. The "second growth," which sprouts from stumps, is most useful, as it splits readily. Fast-growing hickory in rich land is most valuable. The supply of useful hickory is being rapidly exhausted. + +Softness is often important. White pine and sweet gum because of their softness and lightness are useful in boxmaking. "Gnarled" or "sunken" pine is harder and stronger than white pine and is sometimes used for cabinetwork, and some kinds of cabinet work. White pine is used for window sash, doors, and moulding, and cheaper grades are used for flooring. Hemlock is the prevailing lumber in the east for the framework and clapboarding of buildings. Redwood and Douglas fir are common building materials on the Pacific coast. Cypress is soft and resists decay and is superior to white pine for sash, doors, and posts on the outside of houses. Cedar is readily carved and has a unique use in the making of chests for clothes, as its odour repels moths and other insects. Willow is useful for baskets and light furniture. Basswood or Linden is used for light ceiling and sometimes for cheap floors. Whitewood + +70 +**BEECHWOODS' BOTANY** + +(incorrectly called poplar) is employed for wagon bodies and often for house finishing. It often resembles curly maple. + +**Beauty of grain and polish gives wood value for furni- +ture, pianos, and the like. Mahogany and white oak are +most beautiful, although red oak is also used. Oak logs +which are first quartered and then sawn radially expose the +beautiful silver grain (medullary rays). Fig. 86 shows one +mode of quartering. +The log is quartered on the lines a, a', b, b'; then succeeding +boards are cut from each quarter at t, +t', 3, etc. The nearer the heart the better +the "grain"; why? Ordinary boards are +sawn tangentially, as a, c, d, e. +Curly pine, curly fir, cork, cypress, and +bird's-eye maple are woods that owe their +beauty of grain to wavy lines or burried knots. A mere +stump of curly walnut is worth several hundred dollars. +Such wood is sliced very thin for veneering and glued +over other woods in making pianos and furniture. If +the cause of wavy grain could be found out and such wood +grown at will, the discovery would be very useful. Maple is +much used for furniture. Birch may be coloured so as very +closely to represent mahogany, and it is useful for desks. +**Special Products of Tree—Cork:** from the bark of the +cork oak in Spain, latex from the rubber, and sap from the + +Fig. 86.—THE MAKING OF ORDINARY BOARDS, +AND ONE WAY OF MAKING "QUARTERED" BOARD. +Fig. 86 + +THE STEM—ITS GENETAL STRUCTURE + +71 + +sugar-maple trees, tortuipente from pine, tannin from eak bark, Peruvian bark from cinchona, are all useful products. + +**Suggestions.—** Part of a root and stem through which liquids rise. 49. Pull up a small plant with abundant leaves, cut off the root so as to leave two inches or more on the plant (or cut a leafy shoot of sprout or other strong growing cone plant), and stand it in water. The roots will soon grow out of the water, and the leaves with red vein (coccus). After three hours examine the roots; make a section of one of them. What do you find? A long thin cylinder? The cortex? What is your conclusion? Should a small cut flower or a leafy plant with stem in the same solution and examine as before? conclusion? 50. Girdle a twig of a rapidly growing tree with a piece of string, and observe what happens (a) by very carefully removing only the bark, and (b) by cutting away also the sapwood. Under which condition do the leaves wilt? Why? 51. In what way does the stem support its leaves? Formed under the water, girdle the twig (in the two ways) above the roots. What happens to the roots, and why? 52. Observe the swellings on the stems of plants. Are these swellings always in pairs or otherwise: where are these swellings, and why? 53. Kinds of wood. +Let each pupil determine the kind of wood in the desk, the floor boards, the door, the window frame, the shutters, the sash, the shingles, the fence, and in the small implements and furniture in the room; also what is the cheapest and the most expensive lumber in the community. 54. How many kinds of wood are there in your neighborhood? What are they? + +Note to Teacher.—The work in this chapter is intended to be mainly descriptive, for the purpose of giving the pupil a rational conception of the main vital processes associated with the stem. In such a way that he may translate it into daily thought. It is not intended to give him any knowledge of micro- scope. If the pupil is led to make a careful study of the text, drawings, and photographs on the preceding and following pages, he will have gained much valuable information without being forced to spend time in mastering microscope technique. If the school is equipped with compound microscopes, a good deal can be learned by using them. But skill to manipulate them and the knowledge of anatomy and physiology that goes naturally with such work; and it would be useless to give instruction in microscopy unless it was felt that it was of the opinion that the introduction of the compound microscope into first courses in botany has been productive of harm. Good and vital teaching demands that the pupil have a normal, + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
























































































\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\ndetermine the kind of wood in the desk,\nthe floor boards,\nthe door,\nthe window frame,\nthe shutters,\nthe sash,\nthe shingles,\nthe fence,\nand in the small implements and furniture in the room;\nalso what is the cheapest and the most expensive lumber in the community.\n54.\nHow many kinds of wood are there in your neighborhood?\nWhat are they?\nNote to Teacher.—The work in this chapter is intended to be mainly descriptive, for the purpose of giving the pupil a rational conception of the main vital processes associated with the stem.\nIn such a way that he may translate it into daily thought.\nIt is not intended to give him any knowledge of microscope.\nIf the pupil is led to make a careful study of the text, drawings,\nand photographs on the preceding and following pages,\nhimself learn much valuable information without being forced to spend time in mastering microscope technique.\nIf the school is equipped with compound microscopes,\na good deal can be learned by using them.\nBut skill to manipulate them and knowledge of anatomy and physiology that goes naturally with such work;\nand it would be useless to give instruction in microscopy unless it was felt that it was of opinion that introduction of compound microscope into first courses in botany has been productive of harm.\nGood and vital teaching demands that pupil have normal,
Treesfrom pinetannin from eak barkPeruvian bark from cinchonaare all useful products.
Suggestions.Part of a root and stem through which liquids rise.49.Pull up a small plant with abundant leaves,Cut off the root so as to leave two inches or more on the plant (or cut a leafy shoot of sprout or other strong growing cone plant), and stand it in water.The roots will soon grow out of the water, and the leaves with red vein (coccus).After three hours examine the roots;Makes a section of one of them.What do you find?A long thin cylinder?
The cortex?
What is your conclusion?
Should a small cut flower or a leafy plant with stem in the same solution and examine as before?
conclusion?
50.Girdle a twig of a rapidly growing tree with a piece of string,and observe what happens (a)by very carefully removing only the bark,and (b) by cutting away also the sapwood.Under which condition do the leaves wilt?Why?51.In what way does the stem support its leaves?Formed under the water, girdle the twig (in the two ways) above the roots.What happens to the roots,and why?52.Observe the Swellings on the stems of plants.Are these Swellings always in pairs or otherwise: where are these Swellings,and why?53.Kinds of wood.
+ +72 + +BEGINNERS' BOTANY + +direct, and natural relation to his subject, as he commonly meets it, that the obvious and significant features of the plant world would be explained by him without any further explanation. The beginning pupil cannot be expected to know the fundamental physiological processes, nor is it necessary that these processes should be known before he can appreciate the most general principles relating to the things that one customarily sees. Many a pupil has had a so-called laboratory course in botany without having had any real knowledge of the subject. He may have seen, or without having had his mind opened to any real sympathetic touch with his environment. Even if one's knowledge be not deep or extensive, it may still be accurate as far as it goes, and his outlook on the subject may be rational. + +A black and white photograph of a thicket of mangrove trees. +FIG. 87. — THE MANY-STEMMED THICKETS OF MANGROVE OF SOUTHERNSOUTH SEACOASTS, many of the trunks being formed of aerial roots. + +CHAPTER XI + +LEAVES—FORM AND POSITION + +Leaves may be studied from four points of view, — with reference to (1) their kinds and shapes; (2) their position, or arrangement on the plant; (3) their anatomy, or structure; + +A simple netted-veined leaf. +Fig. 85.—A SIMPLE NETTED-VEINED LEAF. + +(4) their function, or the work they perform. This chapter is concerned with the first two categories. + +A compound or branched leaf of brake (a common fern). +Fig. 90.—COMPOUND OR BRANCHED LEAF OF BRAKE (A COMMON FERN). + +Kinds. — Leaves are simple or unbranched (Figs. 88, 89), and compound or branched (Fig. 90). + +74 +BEGINNERS' BOTANY + +The method of compounding or branching follows the mode of veining. +The veining, or venation, is of two general kinds. In some plants the main veins diverge, and there is a conspicuous network of smaller veins; such leaves are netted-veined. They are characteristic of the dicotyledons. In other plants the main veins are parallel, or nearly so, and there is no conspicuous network; these are parallel-veined leaves (Figs. 80, 102). These leaves are the rule in monocotyledonous plants. The venation of netted-veined leaves is pinnate or feather-like when the veins arise from the side of a continuous midrib (Fig. 91); palmate or digitate (hand-like) when the veins arise from the apex of the petiole (Figs. 88, 92). If leaves were divided between the main veins, the former would be pinnately and the latter digitately compound. + +It is customary to speak of a leaf as compound only when the parts or branches are completely separate blades, + +as when the division extends to the midrib (Figs. 90, 93, 94, 95). The parts or branches are known as leaflets. + +Fig. 91.—Coarse-LEAVES OF WILLOW. +Fig. 92.—DIGITATE-VEINED PLE- +TATE LEAF OF NARCISSUM. +Fig. 93.—PINNATY COMPOUND +LEAF OF ABL. + +LEAVES—FORM AND POSITION 75 + +Sometimes the leaflets themselves are compound, and the whole leaf is then said to be bi-compound or twice-com- + +Fig. 94.—Dichotomously Compound Leaf of Balsam Fir. +**Fig. 94. — DICHOTOMOUS COMPOUND LEAF OF BALSAM FIR.** + +pound (Fig. 90). Some leaves are three-compound, four-compound, or five-compound. *Decompound* is a general term to express any degree of compounding beyond twice-compound. + +Leaves that are not divided as far as to the midrib are said to be: + +*lobed*, if the openings or sinuses are not more than half the depth of the blade (Fig. 90); + +*cart*, if the sinuses are deeper than the middle; + +Fig. 95. — Poison Ivy. LEAF AND FRUIT. +**Fig. 95. — POISON IVY. LEAF AND FRUIT.** + +Fig. 96. — Lobed Leaf of Sugar Maple. +**Fig. 96. — LOBED LEAF OF SUGAR MAPLE.** + +76 +BEGINNERS' BOTANY + +parted, if the sinuses reach two thirds or more to the midrib (Fig. 97); divided, if the sinuses reach nearly or quite to the midrib. + +The parts are called lobes, divisions, or segments, rather than leaflets. The leaf may be pinnately or digitately parted or pinnatifid. + +Leaves may have one or more of these parts — blade, or expanded part ; petiole, or stalk ; stipules, or appendages at the base of the petiole. A leaf that has all three of these parts is said to be complete (Figs. 91, 106). The stipules are often green and leaflike and perform the function of foliage as in the pea and the Japanese quince (the latter common in yards). + +Leaves and leaflets that have no stalks are said to be sessile (Figs. 98, 103), i.e. sitting. Find several examples. + +Fig. 97.—Digitately parted leaves of Eucosmia. + +98—OBLONG-SESSILE LEAVES OF TELLA. + +LEAVES—FORM AND POSITION + +The same is said of flowers and fruits. +The blade of a sessile leaf may partly or wholly surround the stem, when it is said to be *clapping*. Examples : aster (Fig. 99), corn. In some cases the leaf runs down the stem, forming a wing ; such leaves are said to be *decurrent* (Fig. 100). When opposite sessile leaves are joined by their bases, they are said to be *connate* (Fig. 101). +Leaflets may have one or all of these three parts, but the stalks of leaflets are called *petiolules* and the stipules of leaflets are called *stipules*. The leaf of the plant is called a *leaf*, leaflets, petiolules, and stipules. + +In pinnate-veined leaves, the petiole seems to continue through the leaf as a *midrib* (Fig. 91). + +In some plants, however, the petiole joins the blade inside or beyond the margin (Fig. 93). Such leaves are said to be *peltate* or shield-shaped. This mode of attachment is particularly common in floating leaves (e.g. the water lilies). Peltate leaves are usually digitately-veined. + +How to Tell a Leaf.—It is often difficult to distinguish compound leaves from leafy branches, and leaflets + +Fig. 99.—Clap- +ing LEAF OF A +WILD ASTER. + +Fig. 100.—De- +current LEAVES OF +MULLEIN. + +Fig. 101.—Two Foli- +es of Connate +Leaves of Honeysuckle. + +78 + +BEGINNERS' BOTANY + +from leaves. As a rule leaves can be distinguished by the following tests: (1) Leaves are temporary structures, sooner or later falling. (2) Usually buds are borne in their axils. (3) Leaves are usually borne at joints or nodes. (4) They arise on wood of the current year's growth. (5) They have a more or less definite arrangement. When leaves fall, the twig that bore them remains; when leaflets fall, the main petiole or stalk that bore them also falls. + +Shapes —Leaves and leaflets are infinitely variable in shape. Names have been given to some of the more definite or regular shapes. These names are a part of the language of botany. The names represent ideal or typical shapes; there are no two leaves alike and very few that perfectly conform to the definition. The shapes are likened to those of familiar objects or of geometrical figures. Some of the commoner shapes are as follows (name original examples in each class): + +Linear, several times longer than broad, with the sides nearly or quite parallel. Spruces and most grasses are examples (Fig. 102). In linear leaves, the main veins are usually parallel to the midrib. + +Oblong, twice or thrice as long as broad, with the sides parallel for most of their length. Fig. 103 shows the short-oblong leaves of the box, a plant that is used for permanent edgings in gardens. + +Fig. 102. +LINEAR—LEAF OF GRASS. + +Fig. 103. +OBLONG—SHORT-OBLONG LEAVES OF BOX. + +Fig. 104. +ACUMINATE LEAF OF GRASS. + +LEAVES—FORM AND POSITION + +79 + +Elliptic differs from the oblong in having the sides gradually tapering to either end from the middle. The European beech (Fig. 104) has elliptic leaves. (This tree is often planted in this country.) + +Lanceolate, four to six times longer than broad, widest below the middle, and tapering to either end. Some of the narrow-leaved willows are examples. Most of the willows and the peach have oblong-lanceolate leaves. + +Spatulate, a narrow leaf that is broadest toward the apex. The top is usually rounded. + +Fig. 105.—Ovate SERIATE LEAF OF HIBISCUS. +Fig. 106.—Leaf of Apple, showing blade, petiole, and small narrow stipules. + +Ovate, shaped somewhat like the longitudinal section of an egg; about twice as long as broad, tapering from near the base to the apex. This is one of the commonest leaf forms (Figs. 105, 106). + +80 + +BEGINNERS' BOTANY + +Obovate, ovate inverted,--the wide part towards the apex. +Leaves of mullein and leaflets of horse-chestnut and false indigo are obovate. This form is commonest in leaflets of digitate leaves: why? + +Reniform, kidney-shaped. This form is sometimes seen in wild plants, particularly in root-leaves. Leaves of wild ginger are nearly reniform. + +Orbicular, circular in general outline. Very few leaves are perfectly circular, but there are many that are nearer circular than of any other shape. (Fig. 107.) + +Illustration of an orbicular leaf. +**Fig. 107.** -- ORBICULAR +LEAFED LEAVES. + +Illustration of a truncate leaf of a tulip tree. +**Fig. 108.** -- TRUNCATE +LEAF OF TULIP TREE. + +The shape of many leaves is described in combinations of these terms: as *ovate-lanceolate*, *lanceolate-oblong*. + +The shape of the base and the apex of the leaf or leaflet is often characteristic. The base may be rounded (Fig. 104), tapering (Fig. 93), cordate or heart-shaped (Fig. 105), truncate or squared as if cut off. The apex may be blunt or obtuse, acute or sharp, acuminate or long-pointed, truncate (Fig. 108). Name examples. + +The shape of the margin is also characteristic of each kind of leaf. The margin is entire when it is not in- dented or cut in any way (Figs. 99, 103). When not + +LEAVES—POEM AND POSITION + +81 + +entire, it may be undulate or wavy (Fig. 92), serrate or saw-toothed (Fig. 105), dentate or more coarsely notched (Fig. 93), crenate or round-toothed, lobed, and the like. +Give examples. + +Leaves on the same plant often differ greatly in form. Observe the different shapes of leaves on the young growths of mulberries (Fig. 2) and wild grapes; also on vigorous squash and pumpkin vines. In some cases there may be simple and compound leaves on the same plant. This is marked in the so-called Boston ivy or ampelopsis (Fig. 104), a vine that is used to cover brick and stone buildings. Different degrees of compounding, even in the same leaf, may often be found among house- plants. Remarkable differenices in forms are seen by comparing seed-leaves with mature leaves of any plant (Fig. 30). + +The Leaf and its Environment.—The form and shape of the leaf often have direct relation to the place in which the leaf grows. Floating leaves are usually expanded and flat, and the petiole varies in length with the depth of the water. Submerged leaves are usually linear or thread-like, or are cut into very narrow divisions; thereby more surface is exposed, and possibly the leaves are less injured by moving water. Compare the sizes of the leaves on the ends of branches with those at the base of the + +Fig. 104.—DIFFERENT FORMS OF LEAVES FROM ONE PLANT OF AMPELOPHIS. + +82 +BEGINNERS' BOTANY + +branches or in the interior of the tree top. In dense foliage masses, the petioles of the lowermost or under-most leaves tend to elongate--to push the leaf to the light. + +On the approach of winter the leaf usually ceases to work, and dies. It may drop, when it is said to be **decidua**; or it may remain on the plant, when it is said to be **persistent**. If persistent leaves remain green during the winter, the plant is said to be **evergreen**. Give examples in each class. Most leaves fall by breaking off at the lower end of the petiole with a distinct joint or articulation. There are many leaves, however, that wither and hang on the plant until torn off by the wind; such as the leaves of grasses, sedges, lilies, orchids, and other plants of the monocotyledons. Most leaves of this character are parallel-veined. + +Leaves also die and fall from lack of light. Observe the yellow and weak leaves in a dense tree top or in any thickets where the lower leaves die on house plants? Note the carpet of needles under the pines! All evergreens shed their leaves after a time. Counting back from the tip of a pine or spruce shoot, determine how many years the leaves persist. In some spruces a few leaves may be found on branches ten or more years old. + +Arrangement of Leaves.--Most leaves have a regular position or arrangement on the stem. This position or direction is determined largely by exposure to sunlight. In temperate climates they usually hang in such a way that they receive the greatest amount of light. One leaf shades another to the least possible degree. If the plant were placed in a new position with reference to light, the leaves would make an effort to turn their blades. + +When leaves are opposite the pairs usually alternate. +That is, if one pair stands north and south, the next pair + +LEAVES—FORM AND POSITION 83 + +stands east and west. See the box-elder shoot, on the left in Fig. 110. One pair does not shade the pair beneath. The leaves are in four vertical ranks. + +There are several kinds of alternate arrangement. In the elm shoot, in Fig. 110, the third bud is vertically above the first. This is true no matter which bud is taken as the starting point. Draw a thread around the stem until the two buds are joined. Set a pin at each bud. Observe that two buds are passed (not counting the last) and that the thread makes one circuit of the stem. Representing the number of buds by a denominator, and the number of circuits by a numerator, we have the fraction $\frac{1}{3}$, which expresses the part of the circle that lies between any two buds. + +That is, the buds are one half of 360 degrees apart, or 180 degrees. Looking endwise at the stem, the leaves are seen to be 2-ranked. Note that in the apple shoot (Fig. 110, right) the thread makes two circuits and five buds are passed: two-fifths represents the divergence between the buds. The leaves are 5-ranked. + +Every plant has its own arrangement of leaves. For opposite leaves, see maple, box elder, ash, lilac, honey-suckle, mint, fuchsia. For 2-ranked arrangement, see all grasses, Indian corn, basswood, elm. For 3-ranked + +Fig. 110.—PHYLLOSTY OF BOX ELDER., ELM, APLER + +84 +BEGINNERS' BOTANY + +arrangement, see all sodes. For 5-ranked (which is one of the commonest) see apple, cherry, pear, peach, plum, poplar, willow. For 8-ranked, see holly, osage orange, some willows. More complicated arrangements occur in bulbs, house leeks, and other `counseled' plants. The buds or "eyes" on a potato tuber, which is an underground stem (why?), show a spiral arrangement (Fig. 111). The arrangement of leaves on the stem is known as **phytolaxy** (literally, "leaf arrangement"). Make out the phytolaxy on six different plants nearest the schoolhouse door. + +In some plants, several leaves occur at one level, being arranged in a circle around the stem. Such leaves are said to be **verticillate**, or **wibed**. Leaves arranged in this way are usually narrow: why? + +Although a definite arrangement of leaves is of no use in the plants, it is subject to modification. On shoots that receive the light only from one side or that grow in difficult positions, the arrangement may not be definite. Examine shoots that grow on the under side of dense tree trunks or in other parts similarly lighted positions. + +SUGGESTIONS. — 55. The pupil should match leaves to determine whether any two are alike: Why? Compare leaves from the same plant but differing in colour; length of petiole; venation, texture (as to thickness or thinness), stage of maturity, smoothness or harshness. 56. Let the pupil take an average leaf from each of the following: oak, maple, birch, elm. Have he meet and compare them as to the above points (in Exerc. c53), and also name the shapes. Determine how the various leaves differ from each other in shape: oak, maple, birch, rose, apple, fig, willow, violet, pea, or others. 58. In what part of the world are parallel-veined leaves the more common? 59. Do + +Fig. 111. +PHYTOLAXY OF THE POSEY LILY FLOWER. +Work 2 out on a fresh longsheet. + +LEAVES—FORM AND POSITION + +you know of parallel-veined leaves that have lobed or dentate mar- +gins? 60. What becomes of dead leaves? 61. Why is there no grass or other undergrowth under pine and spruce trees? +62. What is the use of the leaves of the oak for man? Why are they useful? 63. What trees in your vicinity are most esteemed as shade trees ? What is the character of their foliage ? +64. How do the leaves of the pines differ from those of the oaks? +65. How do foliage characters in corn or sorghum differ when the plants are grown in rows or broadcast? 66. Why ? 67. Why may some vegetables, such as cabbage, cauliflower, cabbages, +beets or lettuce? 68. How do leaves curl when they wither? +Do different leaves behave differently in this respect? 69. What kind of plant is a horse ? A pony ? A mule ? A stallion? +Ivy horses? What kinds are used for human food? 70. How would you describe the shape of leaf of peach? apple? elm? hazel? maple? oak? birch? willow? poplar? strawberry? +cowpen? strawberry? chrysanthemum? rose? carnation? 71. Are any of the foregoing leaves compound? How do you describe the shape of the leaf of a tree or shrub which has no branches you find on the bush or tree nearest the schoolroom door? 72. How many colours or shades? 73. How many lengths of petioles? +74. Bring in all the shapes of leaves that you can find. + +Fig. 11.—Cory. +PEA.—Describe +the leaves. +For +use in the plant +unit. + +85 + +CHAPTER XII + +LEAVES—STRUCTURE OR ANATOMY + +Besides the framework, or system of veins found in blades of all leaves, there is a soft cellular tissue called mesophyll, or leaf parenchyma, and an epidermis or skin that covers the entire outside part. + +Mesophyll.—The mesophyll is not all alike or homogeneous. The upper layer is composed of elongated cells placed perpendicular to the surface of the leaf. These are called palisade cells. These cells are usually filled with green bodies called chlorophyll grains. The grain contains a great number of chlorophyll drops imbedded in the protoplasm. Below the palisade cells is the spongy parenchyma, composed of cells more or less spherical in shape, irregularly arranged, and porous with many intercellular air cavities (Fig. 113). In leaves of some plants exposed to strong light there may be more than one layer of palisade cells, as in the Indian-rubber plant and the oleander. Ivy when grown in bright light will develop two such layers of cells, but in shaded places it may be + +Fig. 113.—Section of a Leaf, showing the various parts. Broughton's leaf-vein diagram, which shows how closely the veins contain the chlorophyll cells in a. Epidermal cells in b. + +86 + +LEAVES—STRUCTURE OR ANATOMY 87 + +found with only one. Such plants as iris and compass plant, which have both surfaces of the leaf equally exposed to sunlight, usually have a palisade layer beneath each epidermis. + +**Epidermis.—** The outer or epidermal cells of leaves do not bear chlorophyll, but are usually so transparent that the green mesophyll can be seen through them. They often become very thick-walled, and are in most plants devoid of all protoplasm except a thin layer lining the walls, the cavities being filled with cell sap. This sap is sometimes coloured, as in the under epidermis of begonia leaves. It is not common to find more than one layer of epidermal cells forming each surface of a leaf. The epi- +dermis serves to retain moisture in the leaf and as a general protective covering. In desert plants the epidermis, as a rule, is very thick and has a dense cuticle, thereby pre- +venting loss of water. + +There are various outgrowths of the epidermis. Hairs are the chief of these. They may be (1) simple, as on primula, geranium, neglecta; (2) once branched, as on wall-flower; (3) compound, as on lily-of-the-valley; (4) double-like, as on shepherds’; (5) stellate, or star-shaped, as in the buttercups. In some cases the hairs are glandular, as in Chinese primrose of the greenhouses (Primula Sinensis) and certain hairs of pumpkin flowers. The hairs often protect the breathing pores, or stomates, from dust and water. + +**Stomates** (sometimes called **breathing-pores**) are small openings or pores in the epidermis of leaves and soft stems that allow the passage of air and other gases and vapours (stomate or stomata, singular; stomates or stomata, plural). They are placed near the large intercellular spaces of the mesophyll, usually in positions least affected by direct + +88 +BEGINNERS' BOTANY + +sunlight. Fig. 114 shows the structure. There are two guard-cells at the mouth of each stomate, which may in most cases open or close the passage as the conditions of the atmosphere may require. The guard-cells contain + +Fig. 114.—DIAGRAM OF STOMATE OF IRIIS (Orchis). Showing compound guard-cells. +Fig. 115.—STOMATE OF IVY, showing compound guard-cells. + +chlorophyll. In Fig. 115 is shown a case in which there are compound guard-cells, that of ivy. On the margins of certain leaves, as of Tuchia, Impatiens, cabbage, are openings known as water-pores. + +**Stomates are very numerous**, as will be seen from the numbers showing the pores to each square inch of leaf surface : + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Lower surfaceUpper surface
Pomey1-73%0-6%
Holly6-7%None
Lilac160-00%None
Mistletoe200200
Trofeasquilla20002000
Garden Flag (Iris)11-57%11-57%
+ +The arrangement of stomates on the leaf differs with each kind of plant. Fig. 116 shows stomates and also the outlines of contiguous epidermal cells. + +The function or work of the stomates is to regulate the passage of gases into and out of the plant. The directly active organs or parts are guard-cells, on either side the opening. One method of opening is as follows: The + +Fig. 116.—STOMATES OF GERANIUM LEAF. + +88 + +LEAVES—STRUCTURE OR ANATOMY + +thicker walls of the guard-cells (Fig. 114) absorb water from adjacent cells, these thick walls buckle or bend and part from one another at their middles on either side of the opening, causing the stomate to open, when the air gases may be taken in and the leaf gases may pass out. When moisture is reduced in the leaf tissue, the guard-cells part with some of their contents, the thick walls straighten, and the faces of the two opposite ones come together, thus closing the stomate and preventing any water vapour from passing out. When a leaf is actively at work making new organic compounds, the stomates are usually open; when unfavourable conditions arise, they are usually closed. They also commonly close at night, especially when (or the increasing of the nocturnal) is most likely to be active. It is sometimes safer to fungigate greenhouses and window gardens at night, for the noxious vapours are less likely to enter the leaf. Dust may clog or cover the stomates. Rains benefit plants by washing the leaves as well as by providing moisture to the roots. + +Lenticels. — On the young woody twigs of many plants (marked in oisers, cherry, birch) there are small corky spots or elevations known as lenticels (Fig. 117). They mark the location of some loose cork cells that function as stomates, for green shoots, as well as leaves, take in and discharge gases; that is, soft green twigs function as lenticels. Under some of these twig stomates, corky material may form and the opening is torn and enlarged; *the lenticels* are successors to the stomates. The stomates lie in the epidermis. + +Fig. 117.—Les- ticles on a twig of a Shoot of RED OAK (CORNUS). + +89 + +90 + +**DERMIS**, but as the twig ages the epidermis perishes and the bark becomes the external layer. **Gases continue to pass in and out through the lenticels, until the branch becomes heavily covered with thick, corky bark. With the growth of the twig, the lenticel scars enlarge longitudinally or crosswise or assume other shapes, often becoming characteristic markings. + +**FIBRO-VEASCULAR BUNDLES.** — We have studied the fibro-vascular bundles of stems (Chap. X). These stem bundles continue into the leaves, ramifying into the veins, carrying the soil water upwards and bringing, by diffusion, the elaborated food out through the sieve-cells. Cut across a petiole and notice the hard spots or arcs in it; strip these parts longitudinally of the petiole. What are they? Full of starch, which is stored during the summer months, when the season's work for the leaf is ended, the nutritious matter may be withdrawn, and a layer of corky cells is completed over the surface of the stem where the leaf is attached. The leaf soon falls. It often fades even before it is killed by frost. Deciduous leaves begin to show the surface line of articulation in the early growing season. This articulation may be observed at any time during the summer. The area of the twig once covered by the petiole is called the leaf-scar after the leaf has fallen. In Chap. XV are shown a number of leaf-scars. In the plane tree (sycamore or buttonwood), the leaf-scar is in the form of a ring surrounding the bud, for the bud is covered by the hollowed end of the petiole; the leaf of sumac is similar. Examine with a hand lens leaf-scars of several woody plants. Note the number of bundle-scars in each leaf-scar. Sections may be cut through a leaf-scar and examined with the microscope. Note the character of cells that cover the leaf-scar surface. + +LEAVES—STRUCTURE OR ANATOMY 91 + +**SUGGESTIONS.—To study epidermal hairs:** 75. For this study, use the leaves of any hairy or woolly plant. A good hand lens will reveal the identity of many of the coarser hairs. A dissecting microscope is necessary. A compound microscope is necessary. Cross-sections may be made so as to bring hairs on the edge of the sections; or in some cases, the hairs may be separated by a thin knife blade and placed in water on a slide. Make sketches of the different kinds of hairs. **76. It is good practice for the pupil to describe leaves in respect to their size, shape, color, and texture.** 77. What kind of hair is on your leaves? On hairy? Wooly? Thickly or thinly hairy? Hairs long or short? Standing straight out or lying close to the surface of the leaf? +**Simple or branched?** At what part of the stem do they appear? **On upper or lower surface of young leaves or old?** 77. Fine a hairy or wooly leaf under water. Does the hairy surface appear silvery? Why? **Other questions:** 78. Why is it good practice to make cross-sections of leaves? 79. How many kinds of hairs are on six kinds of plants: size, shape, color, position with reference to the bud, bundle-scars. 80. Do you find leaf-scars on mono- +cotyledons? 81. Are there leaf-scars on the stems of sunflower, palma, bamboo, green briar? 81. Note the table on page 60. +Can you suggest a reason why there are equal numbers of stomata on upper and lower surfaces of leaves? 82. Can you suggest a reason why there are more stomata on upper surface of other leaves? Suppose you pick a leaf of lime (or some larger leaf), seal the petiole with wax and then rub the upper surface with a piece of glass paper. What happens to the upper surface; which leaf withers first, and why? Make a similar experiment with iris or blue flag. 82. Why do leaves and shoots of home plants have stomata on both sides? What happens to leaves when they are suddenly turned around? 83. Note position of leaves of bean, clover, oxalis, alalfa, locust, at night. + +A diagram showing the structure of a leaf. + +CHAPTER XIII + +LEAVES — FUNCTION OR WORK + +We have discussed (in Chap. VII) the work or function of roots and also (in Chap. X) the function of stems. +We are now ready to complete the view of the main vital activities of plants by considering the function of the green parts (leaves and young shoots). + +Sources of Food. — The ordinary green plant has but two sources from which to secure food,—the air and the soil. +When a plant is thoroughly dried up, all of its green matter passes off; this water comes from the soil. The remaining part is called the ash, or residue or dry matter. If the matter is burned in an ordinary fire, only the ash remains; this ash came from the soil. The part that passed off as gas in the burning contained the elements that came from the air; it also contained some of those that came from the soil—all those (as nitrogen, hydrogen, chlorine) that are transformed into gases by the heat of a common fire. The part that comes from the soil (the ash) is small in amount, being considerably less than to per cent and sometimes less than 1 per cent. Water is the most abundant single constituent or substance of plants. In a corn plant of the roasting-ear stage, about 80 per cent of the substance is water. A fresh turnip is over 90 per cent water. Fresh wood of the apple tree contains about 45 per cent of water. + +Carbon. — Carbon enters abundantly into the composition of all plants. Note what happens when a plant is burned + +92 + +LEAVES--FUNCTION OR WORK + +without free access of air, or smothered, as in a charcoal pit. A mass of charcoal remains, almost as large as the body of the plant. Charcoal is almost pure carbon, the ash present being so small in proportion to the large amount of carbon that we look on the ash as an impurity. Nearly half of the dry substance of a tree is carbon. Carbon goes off as a gas when the plant is burned in air. It does not go off alone, but in combination with oxygen in the form of carbon dioxide gas, CO$_2$. + +The green plant secures its carbon from the air. In other words, much of the solid matter of the plant comes from one of the gases of the air. By volume, carbon dioxide forms only a small fraction of 1 per cent. of the air. It would be very disastrous to animal life, however, if this percentage were much increased, for it excludes the life-giving oxygen. Carbon dioxide is often called "food gas." It may accumulate in old wells, and in experiments upon sheep will not develop well, and they have been tested with it. If the air in the well will not support combustion--that is, if the torch is extinguished--it usually means that carbon dioxide has drained into the place. The air of a closed schoolroom often contains far too much of this gas, along with little solid particles of waste matters. + +Carbon dioxide is often known as carbolic acid gas. + +**Appropriation of the Carbon.--The carbon dioxide of the air readily diffuses itself into the leaves and other green parts of the plant. The leaf is delicate in texture, and when very young the air can diffuse directly into the tissues. The stomates, however, are the special inlets adapted for the admission of gases into the leaves and other green parts. Through these stomates, or diffusion-pores, the outside air enters into the air-sacs of the plant; and is finally absorbed by the little cells containing the living matter.** + +94 +BEGINNERS' BOTANY + +Chlorophyll ("leaf green") is the agent that secures the energy by means of which carbon dioxide is utilized. This material is contained in the leaf cells in the form of grains (p. 80); the gramine themselves are protoplasm, only the colouring matter being chlorophyll. The chlorophyll bodies or grains are often most abundant near the upper surface of the leaf, where they can secure the greatest amount of light. Without this green colouring matter, there would be no reason for the large flat surfaces which the leaves possess, and no reason for the fact that the leaves are borne abundantly at the ends of branches, where the light is most available. Plants with coloured leaves as coleus, have chlorophyll, but it is masked by other colouring matter. This other colouring matter is usually soluble in hot water; both a coleus leaf and notice that it becomes green in hot water and the water becomes coloured. + +Plants grown in darkness are pale and colourless, and do not absorb light. Compare the potato sprouts that have grown from a tuber lying in a dark cellar with those that have grown normally in the bright light. The shoots have become slender, and are devoid of chlorophyll; and when the food that is stored in the tuber is exhausted these shoots will have lived useless lives. A plant that has been grown in darkness from the seed will soon die, although for a time the little seedling will grow very tall and slender. Why? Light favours the production of chlorophyll, and the chlorophyll is the agent in the making of the organic carbon compounds. Sometimes chlorophyll is found in buds and seeds, but in most cases these places are not perfectly dark. Notice how potato tubers develop chlorophyll; it becomes green when exposed to light. + +**Phytoplankton** - Green algae differ greatly in their life; during sunlight it is used, and oxygen is given off. How + +LEAVES—FUNCTION OF WORK + +95 + +the carbon dioxide which is thus absorbed may be used in making an organic food is a complex question, and need not be studied here. It may be stated that carbon dioxide and water are the essentials. Complex compounds are built up out of simpler ones. + +Chlorophyll absorbs certain light rays, and the energy thus directly or indirectly obtained is used by the living matter in building the carbon dioxide absorbed from the air with some of the water brought up from the roots. The ultimate result usually is starch. The process is obscure, but sugar is generally one step; and our first definite knowledge of the product begins when starch is deposited in the leaves. The process of using the carbon dioxide of the air has been known as carbon assimilation, but the term now most used is **photosynthesis** (from two Greek words meaning light and placing together.). + +**Starch and Sugar.—All starch is composed of carbon, hydrogen, and oxygen (C,H,O). All sugars are similar to it in composition. All these substances are called carbohydrates. In making fruit sugar from the carbon and oxygen of carbon dioxide and from the hydrogen and oxygen of the water, there is a surplus of oxygen (6 parts O$_{2}$ + 6 parts H$_{2}$O — C$_{6}$H$_{12}$O$_{6}$ + 6 O$_{2}$). O$_{2}$ is this oxygen that is given off into the air during sunlight. + +**Digestion.—Starch is in the form of insoluble granules. When such food material is carried from one part of the plant to another for purposes of growth or storage, it is made soluble before it can be transported. When this starchy material is transferred from place to place, it is usually changed into sugar by the action of a diastase. This is a process of digestion. It is much like the changing of starchy foodstuffs to sugary foods effected by the saliva.** + +A diagram showing the process of photosynthesis. + +96 +BEGINNEKS' BOTANY + +Distribution of the Digested Food. — After being changed to the soluble form, this material is ready to be used in growth, either in the leaf, in the stem, or in the roots. With other more complex products it is then distributed throughout all the growing parts of the plant; and when passing down to the root, it seems to pass more readily through the inner bark, in plants which have a definite bark. This gradual downward diffusion through the inner bark of materials suitable for growth is the process referred to when the "descent of sap" is mentioned. Starch and other products are often stored in one growing season to be used in the next season. Soil. If a tree constructed of straggling twigs a wire around its trunk (Fig. 118), the digested food cannot readily pass down and it is stored above the girdle, causing an enlargement. + +Assimilation. — The food from the air and that from the soil unite in the living tissues. The "sap" that passes upwards from the roots in the growing season is made up largely of the soil water and the salts which have been absorbed in the diluted solutions (p. 67). This upward-moving water is conducted largely through certain tubular canals of the young wood. These cells are never continuous tubes from root to leaf; but the water passes readily from one cell or canal to another in its upward course. + +The upward-moving water gradually passes to the growing parts, and everywhere in the living tissues, it is, of + +Fig. 118.—Trunk Girdled by a Wire. See Fig. 117. + +LEAVES—FUNCTION OR WORK + +97 + +course, in the most intimate contact with the soluble carbo- +hydrates and products of photosynthesis. In the build- +ing up or reconstructive and other processes it is therefore +assumed that the primary function of certain of the +simpler organic molecules is passing through a series +of changes, gradually increasing in complexity. There will +be formed substances containing nitrogen in addition to +carbon, hydrogen, and oxygen. Others will contain also +sulphur and phosphorus, and the various processes may +be thought of as culminating in protoplasm. +Protoplasm is the living matter in plants. It is in the cells, and is +usually semifluid. Starch is not living matter. The +complex process of building up the protoplasm is called +assimilation. + +Respiration. — Plants need oxygen for respiration, as +animals do. We have seen that plants need the carbon +dioxide of the air. To most plants the nitrogen of the air is inert, and serves only to dilute the other elements; but +the oxygen is necessary for all life. We know that all +animals need this oxygen in order to breathe or respire. +In fact, they have become accustomed to it in just the +proportions found in the air; and this is now best for them. +The air is breathed into the lungs, where it makes +foal, because they use some of the oxygen and give off +carbon dioxide. Likewise, all living parts of the plant must +have a constant supply of oxygen. Roots also need it, for +they respire. Air goes in and out of the soil by diffusion, +and as the soil is heated and cooled, causing the air to +expand and contract. + +The oxygen passes into the air-spaces and is absorbed +by the moist cell membranes. In the living cells it makes +possible the formation of simpler compounds by which +energy is released. This energy enables the plant to + +98 + +**BEGINNING ROTATION** + +work and grow, and the final products of this action are carbon dioxide and water. As a result of the use of this oxygen by night and by day, plants give off carbon dioxide. +Plants respire; but since they are stationary, and more or less inactive, they do not need so much oxygen as animals do, and they do not give off so much carbon dioxide. A few plants in a sleeping room need not disturb one more than a family of mice. It should be noted, however, that germinating seeds respire vigorously, hence they consume much oxy- +gen; and opening buds and flowers are likewise active. + +**Transpiration**—Much more water is absorbed by the roots than is used in growth, and this surplus water passes from leaves into the atmosphere by an evaporation process known as **transpiration**. Transpiration takes place most abundantly from the under surfaces of leaves, and through the pores or stomates. A sunflower plant of the height of a man, during an active period of growth, gives off a quart of water per day. A large oak tree may transpire 150 gallons per day during the summer. For every ounce of dry matter produced, it is estimated that 1 to 25 pounds of water usually passes through the plant. + +When the roots fail to supply the plant sufficient water to equalize that transpired by the leaves, the plant wilt. +Transpiration from the leaves and delicate shoots is in- +creased by all the conditions which increase evaporation, +such as higher temperature, dry air, or wind. The stomata open and close, tending to regulate transpiration as the varying conditions of the atmosphere affect the moisture content of the plant. However, in periods of drought or of very hot weather, and especially during a hot wind, the closing of these stomates cannot sufficiently prevent evaporation. The roots may be very active and yet fail to absorb sufficient moisture to equalize that given + +LEAVES—FUNCTION OR WORK + +99 + +off by the leaves. The plant shows the effect (how?) On a hot dry day, note how the leaves of corn "roll" tow- ards afternoon. Note how fresh and vigorous the same leaves appear early the following morning. Any injury to the roots, such as a bruise, or exposure to heat, drought, or cold may cause the plant to wilt. + +Water is forced up by root pressure or sap pressure. +(Exercise 9.) Some of the dew on the grass in the morn- +ing may be the water forced up by the roots; some of it is +the condensed vapour of the air. + +The wilting of a plant is due to the loss of water from +the cells. The cell walls are soft, and collapse. A toy +balloon will not burst although it is inflated with air +or oxygen. In the woody plants, however, the cell walls may be stiff enough to support themselves, even though +the cell is empty. Measure the contraction due to wilt- +ing and drying by tracing a fresh leaf on page of note- +book, and then tracing the same leaf after it has been +dried between papers. The softer the leaf, the greater +will be the contraction. + +Storage.—We have said that starch may be stored in +twigs to be used the following year. The very early flowers +on fruit trees, especially those that come before the leaves, +and those that come from bulbs, as crocuses and tulips, +are supported by the starch or other food that was organ- +ized the year before. Some plants have very special stor- +age reserves, as the potato, in this case being a thickened +stem although growing underground. (Why a thickened +stem? p. 84.) It is well to make the starch test on winter +twigs and on all kinds of thickened parts, as tubers and bulbs. + +Carnivorous Plants.—Certain plants capture insects and +other very small animals and utilize them to some extent +as food. Such are the sundew, which has on the leaves + +100 + +**BEGINNERS' BOTANY** + +sticky hairs that close over the insect; the Venus's fly-trap of the Southern States, in which the halves of the leaves close over the prey like the jaws of a steel trap; and the various kinds of pitcher plants that collect insects and other organic matter in deep, water-filled, flask-like leaf pouches (Fig. 119). + +The sundew and the Venus's fly-trap are sensitive to contact. Other plants are sensitive to the touch without being insectivorous. The common cultivated sensitive plant is an example. + +This is readily grown from seeds (sold by seedsmen) in a warm place. Related wild plants in the south are sensitive. The utility of this sensitiveness is not understood. + +**Parts that Simulate Leaves** + +We have learned that leaves are endlessly modified to suit the conditions in which the plant is placed. The most marked modifications are in adaptation to light. On the other hand, other organs often perform the functions of leaves. Green shoots function as leaves. These shoots may look like leaves, in which case they are called *cladophylla*. The foliage of common asparagus is made up of fine branches; the real morphological leaves are the minute dry functionless scales at the bases of these branchlets. (What reason is there for calling them leaves?) The broad "leaves" of the *florist's* smilax are cladophylla. Where are the leaves on this plant? Most of the cacti, the entire plant body performs the functions of leaves until the parts become cork-bound. + +The Common Sundew (Drosera rotundifolia), showing its tubular flowers and the call-linguished leaves. + +LEAVES—FUNCTION OR WORK 101 + +Leaves are sometimes modified to perform other functions than the vital processes: they may be tendrils, as the terminal bracts of pen and sweet pea; or spines, as in barberry. Not all spines and thorns, however, represent modified leaves: some of them (as of hawthorns, osage orange, honey locust) are branches. + +**Suggestions.—To test for chlorophyll.** § 4. Annotate about a gill of water alcohol. Secure a leaf of geranium, cherry, or other plant that has been exposed to sunlight for a few hours, and, after drying on paper towel, place it in a test-tube containing a drop of water with sufficient alcohol to cover. Place the cup in a shallow pan of hot water on the stove where it is not hot enough for the alcohol to take fire. After a time the chlorophyll is dissolved by the alcohol and the green color appears in the water. This is a test for the starch experiment (Exercise 5). Without chlorophyll, the plant cannot appropriate the carbon dioxide of the air. Starch and photosynthesis are thus related. + +A leaf which has been exposed to sunlight but in the dark no starch can be formed from carbon dioxide. Apply boiling to the leaf from which the chlorophyll was dissolved in the previous experiment. Note that the leaf is coloured purplish-brown throughout. The leaf cannot assimilate carbon dioxide. + +Cure a leaf from a plant which has been in the dark for several days. + +Dissolve the chlorophyll as before, and extract to stain this leaf with iodine. The leaf will turn purple when treated with iodine. This shows that the starch manufactured in the leaf may be entirely converted into starch. + +§ 67. Secure a plant which has been kept in darkness for two weeks. Cut off one of its leaves. Split a small cork and pin the two halves on opposite sides of one of the leaves, as shown in Fig. 131. Place these plates in a test-tube with water and alcohol; then place another plate over them and dissolve the chlorophyll in this leaf with alcohol; then stain the leaf with the iodine. Notice that the leaf is stained deeply except where the cork was; there sunlight and carbon dioxide were combined. Fig. 131. There is no starch in the + +covered area. 88. Plants or parts of plants that have developed no chlorophyll can form no starch. Secure a variegated leaf of coleus, ribbon grass, or other plant with leaves showing both green and grey. On a day of bright sunshine, extract some of these leaves by the alcohol and iodine method for the presence of starch. Observe that the parts devoid of green colour have formed no starch. However, although the starch has been removed, it may be to be again the living converted into starch in certain other parts of tissues. + +89. To show the escape of oxygen. Make the experiment illus- +trated in Fig. 125. Under a fun- +nel in a vessel containing fresh spring or stream water place fresh pieces of the common water lily (Nymphaea). Have the funnel considerably smaller than the vessel, and sup- +port it so that it rests on the bot- +tom so that the plant can more +readily get all the carbon dioxide available. The water will soon boil +boiled water be undesirable in this +experiment? For a home-made glass funnel, crack the bottom off a carton box, and then press +ing a red-hot poker or iron rod against it and leading the crack upwards to make a test tube over the stem of the fun- +nel. In sunlight bubbles of +oxygen will rise up to meet +the test-tube. If a sufficient quantity of oxygen has collected, +a bubble will rise to the top of the +tube will glow with a brighter flame, showing the presence of oxygen in greater quantity than in the air. Shade the vessel. +Are bubbles produced at night? For many reasons it is desirable to continue this experiment for several hours. 90. A simpler experiment may be made if one of the waterweeds Cabomba (water-lily family) is available. Take a number of branches together with their roots, and place them in a large vessel of spring water, and insert a test-tube of water as before over the bundle. The lobules will arise from the cut surfaces. Observe the lobules on pond sand and water +weeds on a sunny day. To illustrate the results of respiration + +Fig. 125.—To show the escape of oxygen. + +LEAVES--FUNCTION OR WORK 103 + +(ÇO). 91. In a jar of germinating seeds (Fig. 123) place carefully a small dish of limewater and cover tightly. Put a similar dish in another jar of about the same size, but without seeds. After a few hours compare the cloudi- +ness or precipitate in the two jars. + +92. Or, place a growing plant in a deep covered jar of water, cork, and after a few hours in- +sert a lighted candle or lamp, and observe the effect. A similar experiment with fresh roots of bents or other plants, in which the leaves are mostly removed. +The jar need not be kept closed. In this case, to test the respiration of a shoot of any plant, thrust the end of it through a hole in a cork, and stand it in a small bottle of water. Invert over this a fruit jar, and allow that a mist soon accumulates on the inside of the glass. In time drops of water form. The experi- +ment may be varied as shown in Fig. 126, taking care to cover the soil with oiled paper or cloth to prevent evaporation from the soil. A test may also be made by placing the pot, properly protected, on lab. + +FIG. 123.--TO ILLU- +TRATE A PRODUCT OF +RESPIRATION. + +To test respiration. 94. Cut a succulent shoot of any plant, thrust the end of it through a hole in a cork, +and stand it in a small bottle of water. Invert over this a fruit jar, and allow that a mist soon accumulates on the inside of the glass. In time drops of water form. The experi- +ment may be varied as shown in Fig. 126, taking care to cover the soil with oiled paper or cloth to prevent evaporation from the soil. A test may also be made by placing the pot, properly protected, on lab. + +FIG. 125.--TO ILLUSTRATE TRANSPIRATION. + +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. +A diagram showing a plant's root system with roots extending into the soil. + +104 +BEGINNERS' BOTANY + +ances, and the loss of weight will be noticed (Fig. 127). 96. Cut a winter twig, seal the severed end with wax, and allow the twig to lie several days. If the twig is kept in water, the upward movement of water even in winter, else plants would shrivel and die. 99. To illustrate sap pressure, take a glass tube with an upward movement of sap water often taken from a tree trunk. The cause of this force, known as root pressure, is now understood. The pressure varies under different plants and under different conditions. To illustrate: cut off a strong-growing branch from the ground. By means of a bit of wax, seal the stem with a glass tube with a bore of approxi- +125. — TO ILLUSTRATE TRANSLATION. +mately one-eighth the diame- +ter of the stem. +Pour in a little +sugar. Observe +the rise of the +water due to the +pressure from the +stem. + +low (Fig. 128). Some plants yield a large amount of water under a pressure sufficient to raise a column several feet; others force out only a consider- +able pressure (less easily demon- +strated). The vital pro- +cesses (i.e., the life process). + +100. The pupil has studied wood, stems, and leaves, should now be able to describethe main vital functions of plants: what is meant by "the 'sip'? 101. Where and how does the plant secure its water? energy? car- +bon dioxide? nitrogen? +127. — LOSS OF WATER. +128. — TO SHOW SAP PRESSURE. + +stem function? leaf function? 101. What is meant by the "sip"? 102. Where and how does the plant secure its water? energy? car- +bon dioxide? nitrogen? +129. — TO SHOW SAP PRESSURE. + +**LEAVES—FUNCTION OR WORK** + +105 + +*alum? iron? phosphorus?* 103. Where is all the starch in the world made? What does a starch-factory establishment do? +Where are the real starch factories? 104. In what part of the plant is starch formed most rapidly? How is it stored? Is it likely to be found in the field, in the soil, under the ground, or under water? 105. Why does corn or cotton turn yellow in a field after being cut? Why are corn stalks, or cotton stalks, or cotton stalks burned in the field, if as much plant-food returned to the soil as was removed by cutting? + +*What process of plants is roughly analogous to perspiration of animals?* 106. Why do we say that the human world uses raw mineral for food? 109. Why is earth banked over celery to bleach it? 110. Why is a tree pruned so that its wood may be equal to the amount absorbed? 111. Give some reasons why plants very close to a house grow more luxuriant than those farther away. + +*Why are fruit-trees pruned or thinned out as in Fig. 129.* 112. Proper balance between top and root. 113. Why is it necessary that the top and the root parts work together. They may be said to balance each other in activities, the root supplying the food and the top producing (how?) If half the roots were cut from a tree, we should expect to reduce the top also, perhaps to death. Would you like to know how would you prune a tree or bush that is being transplanted? Fig. 130 may be suggestive. + +Fig. 130.—Before and after pruning. +fig. 130—AN APPLE TREE, with suggestions as to pruning when it is young, and as it is shown a pruned top. + +**TEXTS WITH Suggestions** + +As no peeling when it is young, and as it is shown a pruned top. + +CHAPTER XIV + +DEPENDENT PLANTS + +Thus far we have spoken of plants that have roots and foliage and that depend on themselves. They collect the raw materials and make them over into assimilable food. They are independent. Plants without green foliage cannot make food; they must have it for them or they die. They are dependent. A sprout from a potato tuber in a dark cellar cannot collect and elaborate carbon dioxide. It lives on the food stored in the tuber. + +Fig. 131. — A mushroom, example of a sapen- +phytic plant. This is the edible cultivated +mushroom. +All plants with natu- +rally white or bluish parts are dependent. Their leaves do not develop. They live on organic matter—that which has been made by a plant or elaborated by an animal. The dodder, Indian pipe, beech drop, coral root among flower-bearing plants, also mushrooms and other fungi (Figs. 131, 132) are examples. The dodder is common in swamps, being conspicuous late in the summer, from its long, leafless, yellow-orange stems spreading over the herbage of other plants. One kind attacks alfalfa and is a leaf pest. The sevul gynain- +ate in the spring, but as soon as the twining stem a- 106 + +DEPENDENT PLANTS +107 + +taches itself to another plant, the dod- +der dies away at the base and becomes +wholly dependent. It produces flowers +in clusters and seeds itself freely +(Fig. 133). + +**Parasites and Saprophytes.** — A plant +that is dependent on a living plant or +animal is a **parasite**, and the plant or +animal on which it lives is the **host**. +The dodder is a true parasite; so are +the rusts, mildews, and other fungi that +attack leaves and shoots and injure them. + +A diagram showing a parasitic fungus, magnified. The mycelium, or vegetative part, is shown by the dotted- +shaded lines. The spores are shown by the leaf figure. The rounded host- +cells are shown by the cells in the leaf figure. The long, thin, thread-like +fungus hangs from the under surface of the leaf. +Fig. 133.—A PARASITIC FUNGUS, magnified. + +The threads of a parasitic fungus usually creep through the intercellular +spaces in the leaf or the stem and send +suckers (or haustoria) into the cells +(Fig. 132). The threads (or the hy- +phae) cling to the upper surface of the leaf +and often plug the stomata, +so that they also appropriate and +disorganize the cell fluids; thus +they injure or kill their host. The mass of hyphae +of a fungus is called **mycelium**. Some of the +hyphae finally grow out of the leaf and produce +spores or reproductive cells that an- +swer the purpose of seeds in distrib- +uting the plant (6, Fig. 132). +A plant that lives on dead or de- +caying matter is a **saprophyte**. Mush- +rooms (Fig. 131) are examples; they +live on the decaying matter in the +mould on bread and cheese is an + +A diagram showing a mushroom growing from fruit. +Fig. 132.—DEAD LEAF IN FRUIT. + +6 + +108 + +BEGINNERS' BOTANY + +example. Lay a piece of moist bread on a plate and invert a tumbler over it. In a few days it will be mouldy. +The spores were in the air, or perhaps they had already fallen on the bread but had not had opportunity to grow. +Most green plants are unable to make any direct use of the humus or vegetable mould in the soil, for they are not saprophytic. The shell-fungi (Fig. 134) are saprophytes. They are common on logs and trees. Some of them are perhaps parasitic upon parasites, extending the mycelium into the wood of the living tree and causing it to become black-hearted (Fig. 134). + +Some parasites spring from the ground, as other plants do, but they are parasitic on the roots of their hosts. Some parasites may be partially parasitic and partially saprophytic. Many (perhaps most) of these ground saprophytes are aided in securing their food by soil fungi, which spread the root-like branches of the plant and act as intermediaries between the food and the saprophyte. These fungus-covered roots are known as *mycorrhizas* (meaning "fungus root"). Mycorrhizas are not peculiar to saprophytes. They are found on many wholly independent plants, as, + +Tiny tree fungus (Phytophthora gigantea) on bark log. The cut-out part of the fungus is shown below; the host-cut injury above. +Fig. 134 — Tiny tree fungus (Phytophthora gigantea) on bark log. The cut-out part of the fungus is shown below; the host-cut injury above. + +108 + +DEPENDENT PLANTS 109 + +for example, the heaths, oaks, apples, and pines. It is probable that the fungous threads perform some of the offices of root-hairs to the host. On the other hand, the fungus obtains some nourishment from the nest. The association seems to be mutual. + +**Saprophytes** break down or decompose organic substances. Chief of these saprophytes are many microscopic organisms, is known as bacteria (Fig. 135). These immemorable organisms are immersed in water or in dead animals and plants, and in all manner of moist organic products. By breaking down organic combinations, they produce decay. Largely through their agency, and that of many true but microscopic fungi, all things pass into soil and gas. Thus are the bodies of plants and animals removed and the continuing round of life is maintained. +Some parasites are green-leaved. Such is the mistletoe (Fig. 136). They anchor themselves on the host and absorb its juices, but they also appropriate and use + +Fig. 135.—BACTERIA OF SEVERAL FORMS, much magnified. + +Fig. 136.—AMERICAN MISTLETOE GROWING ON A WALNUT BRANCH. + +110 +BEGINNERS' BOTANY + +the carbon dioxide of the air. In some small groups of bacteria a process of organic synthesis has been shown to take place. + +Epiphytes.--To be distinguished from the dependent plants are those that grow on other plants without taking food from them. These are green-leaved plants whose roots burrow in the bark of the host plant and perhaps derive some food from it, but which subsist chiefly on materials that they secure from air dust, rain water, and the air. These plants are epiphytes (meaning "upon plants") or air plants. + +Epiphytes abound in the tropics. Certain orchids are among the best known examples (Fig. 37). The Spanish moss or tillandia of the South is another. Mosses and lichens that grow on trees and fences may also be called epiphytes. In the struggle for existence, the plants probably have been driven to these special places in which to find opportunity to grow. Plants grow where they must, not where they will. + +SUGGESTIONS.--114. Is a puffball a plant? Why do you think so? 115. Are mushrooms ever cultivated, and where do they come from? What is their relation to the earth? Are they usually found? (There is really no distinction between mushrooms and toadstools. They are all mushrooms.) 116. What kinds of fungi are used by man? 117. How does the farmer overcome potato blight? Apple scab? Or any other fungous "plant disease"? 118. How do these things injure plants? How can we prevent them? 119. Can you know that every spot or injury on a leaf or stem is caused by something--as an insect, a fungus, wind, hail, drought, or other agency. How many injured or perfect leaves are there on the plant during one day? 120. What is the formula for Bordeaux mixture and tell how and for what it is used. + +CHAPTER XV. + +WINTER AND DORMANT BUDS + +A bud is a growing point, terminating an axis either long or short, or being the starting point of an axis. All branches spring from buds. In the growing season the bud acts as a latent seed, tending to increase the axis in length, and as winter approaches the growing point becomes more or less thickened and covered by protecting scales, in preparation for the long resting season. This resting, dormant, or winter body is what is commonly spoken of as a "bud." A winter bud may be defined as an inactive covered growing point, waiting for spring. + +Structurally, a dormant bud is a shortened axis or branch, bearing miniature leaves or flowers or both, and protected by a covering. Cut in two, lengthwise, a bud of the horse-chestnut or other plant that has large buds. With a pin separate the tiny leaves. Count them. + +Examine the big bud of the rhubarb as it lies under the ground in late winter or early spring; or the crown buds of asparagus, haggetta, or other early spring plants. Dissect large buds of the apple and pear (Fig. 137, 138). + +The bud is protected by firm and dry scales. These scales are modified leaves. The scales fit close. Often + +Fig. 137.—Bud of Apfelstrasse showing the miniature leaves. +Fig. 138.—Bud of Pear, showing the miniature leaves and flowers. The latter are the little cups in the centre. + +111 + +112 +BEGINNERS' BOTANY + +the bud is protected by varnish (see horse-chestnut and the balsam poplar). Most winter buds are more or less woolly. Examine some of them under a lens. As we might expect, bud coverings are most prominent in cold and dry climates. Sprinkle water on velvet or flannel, and note the result and give a reason. + +All winter buds give rise to branches, not to leaves alone; that is, the leaves are borne on the lengthening axis. Sometimes the axis, or branch, remains very short,—so short that it may not be noticed. Sometimes it grows several feet long. + +Whether the branch grows large or not depends on the chance it has,—position on the plant, soil, rainfall, and many other factors. The new shoot is the unfolding and enlarging of the tiny axis and leaves that we saw in the bud. If the conditions are congenial, the shoot may form more leaves than were tucked away in the bud. The length of the shoot usually depends more on the length of the internodes than on the number of leaves. + +**Where Buds Are:** Buds are borne in the axils of the leaves,—in the acute angle that the leaf makes with the stem. When the leaf is growing in the summer, a bud is forming above it. When the leaf falls, the bud remains, and a scar marks the place of the leaf. Fig. 130 shows the large leaf-axils of alth İnsan. Observe those on the horse-chestnut, maple, apple, pear, basswood, or any other tree or bush. + +Sometimes two or more buds are borne in one axil; the extra ones are accessory or supernumerary buds. Observe them in the Tartarian honeysuckle (common in yards), + +Fig. 130.—Leaf-axils.—Alth İnsan. + +WINTER AND DORMANT BUDS +113 + +walnut, butternut, red maple, honey locust, and sometimes in the apricot and peach. + +If the bud is at the end of a shoot, however short the shoot, it is called a terminal bud. It continues the growth of the axis in a direct line. Very often three or more buds are clustered at the tip (Fig. 140); and in this case there may be more buds than leaf scars. Only one of them, however, is strictly terminal. + +A bud in the axil of a leaf is an *axillary* or *lateral* bud. Note that there is normally at least one bud in the axil of every leaf on a tree or shrub in late summer and fall. The axillary buds, if they grow, are the *starting points* of new shoots following winter. If a leaf is pulled off early in summer, what will become of the young bud in its axil? T. T. H. + +Bulbs and cattleya buds may be likened to buds; that is, they are condensed stems, with scales or modified leaves densely overlapping and forming a rounded body (Fig. 141). They differ from true buds, however, in the fact that they are condensations of whole main stems rather than embryo stems borne in the axils of leaves. But bulbils (as of tiger lily) may be scarcely distinguishable from bulbs on the one hand and from bulbs + +A large bulb with multiple layers of overlapping scales. +**Fig. 141.—A Gigantic Bud.—Cattleya.** + +114 +BEGINNERS' BOTANY + +on the other. Cut a cabbage head in two, lengthwise, and see what it is like. + +The buds that appear on roots are unusual or abnormal, —they occur only occasionally and in no definite order. +Buds appearing in unusual places on any part of the plant are called **adventitious buds**. Such usually are the buds that arise when a large limb is cut off, and from which suckers or water sprouts arise. + +**How Buds Open.** +When the bud scales, the scales are pushed open by the little axis down gates and push out. In most plants the outside scales fall very soon, leaving a little ring of scars. With terminal buds, this ring marks the end of the year's growth. How? +Notice peach, apple, plum, willow, and other plants. In some others, all the scales grow for a time, as in the pear (Figs. 142, 143, 144). In other plants the inner bud scales become green and almost leaf-like. See the maple and hickory. + +Sometimes Flowers come out of the Buds.—Leaves may or may not accompany the flowers. We saw the embryo flowers in Fig. 138. The bud is shown again in Fig. 142. In Fig. 143 it is opening. In Fig. 145 + +Fig. 143.—THE OPENING OF THE FRUIT-BUD OF PEAR. + +Fig. 144.—OPENING PEAR LEAF-BUD. + +Fig. 145.—OPENING OF THE FRUIT-BUD. + +WINTER AND DORMANT BUDS +115 + +it is more advanced, and the woolly unformed flowers are appearing. In Fig. 146 the growth is more advanced. + +A small flower bud in the pear cluster, seen at 7 a.m., on the day of its opening, to o'clock it will be fully expanded. +Fig. 146. -- A sm. +GLE FLOWER +IN THE PEAR +CLUSTER, +seen +at 7 a.m., +on the day +of its +opening, +to +o'clock it +will be +fully ex- +panded. + +A bud that contains or produce only leaves are leaf-buds. Those which contain only flowers are flower-buds or fruit-buds. The latter occur on peach, almond, apricot, and many very early spring-flowering plants. The single flower is emerging from the apricot bud in Fig. 147. A longitudinal section of this bud, enlarged, is shown in Fig. 148. Those that contain both leaves and flowers are mixed buds, as in pear, apple, and most late spring-flowering plants. +Buds that contain or produce only leaves are + +A fruit-bud and leafbud of pear. +Fig. 149. -- Fruit-bud +AND LEAF-BUD OF PEAR. + +A bud that contains or produces only leaves are leaf-buds. Those which contain only flowers are flower-buds or fruit-buds. The latter occur on peach, almond, apricot, and many very early spring-flowering plants. The single flower is emerging from the apricot bud in Fig. 147. A longitudinal section of this bud, enlarged, is shown in Fig. 148. Those that contain both leaves and flowers are mixed buds, as in pear, apple, and most late spring-flowering plants. +Buds that contain or produce only leaves are leaf-buds. Those which contain only flowers are flower-buds or fruit-buds. The latter occur on peach, almond, apricot, and many very early spring-flowering plants. The single flower is emerging from the apricot bud in Fig. 147. A longitudinal section of this bud, enlarged, is shown in Fig. 148. Those that contain both leaves and flowers are mixed buds, as in pear, apple, and most late spring-flowering plants. + +Fruit buds are usually thicker or stouter than leaf-buds. They are borne in different positions on different plants. +In some plants (apple, pear) they are on the ends of short branches or spurs; in others (peach, red maple) they are along the sides of the last year's growths. In Fig. 149 are shown + +116 +BEGINNERS' BOTANY + +three fruit-buds and one leaf-bud on $E$, and leaf-buds on $A$. See also Figs. 150, 151, 152, 153, and explain. + +Fig. 190. — Fruit-buds of Apple on spire: a dormant bud at the top. + +Fig. 191. — Clus- +ter of two +fruit-buds of sweet +Cherry, with +a leaf-bud in con- +trol. + +Fig. 192. — Two +fruit-buds +of Plum, +with a leaf- +bud between. + +Fig. 193. — Opening of Leaf-bud and Flower-bud of Apple. +"The burst of spring" means in large part the opening of the buds. Everything was made ready the fall before. The embryo shoots and flowers were tucked away, and the food was stored. The warm rain falls, and the shutters open and the sleepers wake. + +Arrangement of Buds.—We have found that leaves are usually arranged in a definite order; buds are borne in the axils of leaves: therefore buds must exhibit phyllotaxy. + +WINTER AND DORMANT BUDS +117 + +Moreover, branches grow from buds; branches, therefore, should show a definite arrangement. Usually, however, they do not show this arrangement because not all the buds grow and not all the branches live. (See Chaps. II and III.) It is apparent, however, that the mode of arrangement of buds determines to some extent the form of the tree. Compare bud arrangement in pine or fir with that in maple or apple. + +Fig. 153.—Oak Sprat. How are the lower bums with reference to the annual growth? +The uppermost buds on any twig, if they are well matured, are usually the larger and stronger and they are the most likely to grow the next spring; therefore, branches tend to be arranged in tiers (particularly well marked in spruces and firs). See Fig. 154 and explain it. + +Winter Buds show what has been the Effect of Sunlight. +Buds are borne in the axils of the leaves, and the size or the vigour of the leaf determines to a large extent the size of the bud. Notice that, in most instances, the largest buds are nearest the tip (Fig. 157). If the largest buds are not near the tip, there is some special reason for it. Can you state it? +Examine the shoots on trees and bushes. + +**118** + +**BEGINNERS' BOTANY** + +**SUGGESTIONS.** — Some of the best of all observation lessons are those made on dormant twigs. There are many things to be learned, the leaves are retained, and the specimens are everywhere accessible. **123.** At whatever time of year the pupil takes up the study of branches, he will find that they differ greatly in size, in the various parts, the relative positions of the buds and the leaves, the different sizes of similar or comparable bolls. If it is late in spring, and the buds are just beginning to open, he may see how the bolls in the axils, and he should determine whether the strength or size of the bud is in any way related to the size and shape of the leaf. The leaves are usually large when the bud should also be situated on lessed twigs, and the sizes of the former leaves may be inferred from the size of the leaf-cot below the bud. The bud is a place where food is stored, where strength for food and light, and its effects on the developing bolls. + +**124.** The bud and the branch. A twig cut from an apple tree in early spring is shown at fig. 135. The most obvious observa- +tion that can be made has various parts or organs which may be divided at the point f into two parts. It is evident that the part from f to a gives rise to new buds, and that the part f down to g gives two kinds of leaves, one of which is larger than the other, and these differences challenge investigation. In order to understand this seemingly hitherto useless twig, it will be necessary to see it as it looks in winter (fig. 136). The part from f to a, which has just completed its growth, is seen to have its leaves growing singly. In every axil (as indicated by arrows) there is a bud which shows no sign of life. The leaf starts first, and as the season advances the bud forms in its axil. When the leaves have fallen, at the approach of winter, the buds remain alive, and during this period they grow. In last year's growth of a winter twig; therefore, marks the position occupied by a leaf when the shoot was growing. The part below f, in fig. 135, shows that there are two kinds of leaves: some are two-leaved (douay), and there are buds without leaves (blb). A year ago this part looked like the present shoot (fig. 137). Now it is seen that there are three kinds of leaves in it: an oil-leaf, c. It is now seen that some of these bud-like parts are longer than others, and that the longest ones are those which have leaves. It must be observed of these leaves that they have increased in length since their formation by a previous accident, and its growth has ceased. In other words, parts at aon are like the shoot f; except that they are shorter, and their leaves have been shed; but those at blb have remained bud of the main branch, and the others from the side or lateral bolls. Parts or bodies that bear leaves are, therefore, branches. + +—The buds at blb have no leaves, and they remain the same + +WINTER AND DORMANT BUDS 119 + +size that they were a year ago. They are dormant. The only way for a mature bud to grow is by making leaves for itself, for a leaf + +A small twig with several buds at different stages of development. +Fig. 155. — An +Newly Twig. + +A larger twig with more developed buds and leaves, indicating growth over two seasons. +Fig. 156. — Same twig before shown fig. +will never stand below it again. The twig, therefore, has buds of two ages, — those at A and B are two seasons old, and those on the + +tips, all of the branches (axile), and in the axil of every leaf, are one season old. It is only the terminal buds that are not axillary. When the bud begins to grow and to put forth leaves, it gives rise to a branch, which, in its turn, bears leaves. —It will now be interesting to determine why certain buds gave rise to branches and why others remained as buds. The strongest shoot or branch of the tree is the terminal one (fig. 137). The next most vigorous is the second one, and so on. The weakest shoot is at the base of the twig. The thinnest buds are on the under side (for the twig being in a horizontal position). All this suggests that those buds grew which had the best chance,—the best soil, the best light, and the best air. In this way, each year, and in the struggle for existence those that had the best opportu- +nities made the largest growth. This struggle for existence began with the buds near the tip of the twig. Those buds were forming in the axils of the leaves, for the buds near the tip of the shoot grew larger and stronger than those near its base. The greatest number of buds were formed by those conditions under which the buds were formed the previous year. Other bad characters. 125. It is easy to see the swelling of the buds in spring, when they are about two inches long, shrubs, two to three feet long, and stand up in vases or jars, as you would flowers. Renew the water frequently and cut off the leaves when they begin to fall. In early spring or week or two the buds will begin to swell. Of red maple, peach, and apple trees, etc., very early-flowering things, flowers may be obtained in ten to twenty days. 126. The shape, size, and colour of the winter buds are different characters by means of which botanists can often be able to distinguish the kinds of plants. Even such similar plants as the different kinds of willows have good bad characters. For example, there are willows which grow on a pench, plum, and other trees. If different kinds of maples grow in the vicinity, secure twigs of the red or swamp maple, and the soft or silver maple, and compare the buds with those of the sugar maple and the Norway maple. What do you learn? + +Fig. 137.—Buds of the Hickory. + +120 +BEGINNERS' BOTANY + +CHAPTER XVI +BUD PROPAGATION + +We have learned (in Chap. VI) that plants propagate by means of seeds. They also propagate by means of bud parts,—as rootstocks (chickens), roots, runners, layers, bulbs. +The pupil should determine how any plant in which he is interested naturally propagates itself (or spreads its kind). Determine this for raspberry, blackberry, strawberry, Junc-grass or other grass, nut-grass, water lily, May apple or mindrage, burdock, Irish potato, sweet potato, buckwheat, cotton, pea, corn, sugar-cane, wheat, rice. +Plants may be artificially propagated by similar means, as by layers, cuttings, and grafts. The last two we may discuss here. + +Cutting in General—A bit of a plant stuck into the ground stands a chance of growing; and this bit is cutting. Plants have preferences, however, as to the kind of bit which shall be used, but there is no way of telling what this preference is except by trying. In some instances this prefer- ence has not been discovered, and we say that the plant cannot be propagated by cuttings. + +Most plants prefer that the cutting be made of the soft or growing parts (called "wood" by gardeners), of which the "slips" of geranium and coleus are examples. Others grow equally well from cuttings of the hard or mature parts or wood, as currant and grape; and in some instances this mature wood may be of roots, as in the blackberry. In some cases cuttings are made of tubers, as in the Irish + +123 + +122 + +**BEGINNERS' BOTANY** + +potato (Fig. 60). Pupils should make cuttings now and then. If they can do nothing more, they can make cuttings of potato, as the farmer does; and they can plant them in a box in the window. + +The Softwood Cutting — The softwood cutting is made from tissue that is still growing, or at least from that which is not dormant. It comprises one or two joints, with + +A diagram showing a leaf attached to a twig, labeled "FIG. 158 - GERANIUM CUTTING." A second diagram shows a leaf attached to a branch, labeled "FIG. 159 - ROSE CUTTING." + +a leaf attached (Figs. 158, 159). It must not be allowed to wilt. Therefore, it must be protected from direct sunlight and dry air until it is well established; and if it has many leaves, some of them should be removed, or at least cut in two, in order to reduce the evaporating surface. The soil should be uniformly moist. The pictures show the depth to which the cuttings are planted. + +For most plants, the proper age or maturity of wood for the making of cuttings may be determined by giving the twig a quick bend: if it snaps and hangs by the bark, it is in proper condition; if it bends but does not snap, it is too young and soft or too old; if it splinters, it is too old and woody. The tips of strong upright shoots usually make the best cuttings. Preferably, each cutting should have a joint or node near its base; and if the internodes are very short it may comprise two or three joints. + +A diagram showing a leaf attached to a twig, labeled "FIG. 158 - GERANIUM CUTTING." A second diagram shows a leaf attached to a branch, labeled "FIG. 159 - ROSE CUTTING." + +**BUD PROPAGATION** + +The stem of the cutting is inserted one third or more of its length in clean sand or gravel, and the earth is pressed firmly about it. A newspaper may be laid over the bed to ex- +clude the light—if the sun strikes it—and to prevent too rapid evaporation. The soil should be moist clear through, +not on top only. + +When coarse or generally soil is used. Sand used by masons is good material in which to start most cuttings; or fine gravel— sifted of most of its earthy matter—may be used. Soils are avoided which contain much decaying organic matter, for these soils are breeding places of fungi, which attack the soft cutting and cause it to "damp off," or to die at or near the surface of the ground. If the cuttings are to be grown in a window, put three or four inches of the earth in a shallow box or a pan. A soap box cut in two lengthswise, so that it makes a box four or five inches deep—as a gardener's flat—is excellent (Fig. +160). Cuttings of common plants, as geranium, coltsis, fuchsia, carnation, are kept at a living-room temperature. As long as the cuttings look bright and green, they are in good condition. It may be a month before roots form. When roots have formed, the plants begin to make new leaves at the tip. Then they may be transplanted into other boxes or into pots. The verbena in Fig. 161 is just ready for transplanting. + +Fig. 160.—Cerinthe. + +Fig. 161.—Verbena cutting ready for transplanting. + +124 + +**BEGINNERS' GARDEN** + +It is not always easy to find growing shoots from which to make the cuttings. The best practice, in that case, is to cut back an old plant, then keep it some time, and when it is well grown, and thereby force it to throw out new shoots. The old geranium plant from the window garden, or the one taken up from the lawn bed, may be treated this way (see Fig. 162). The best plants of geranium and coleus and most window plants are those which are not more than one year old. The geranium and fuchsia cuttings which are made in January, February, or March will give compact blooming plants for the next winter; and thereafter new ones should take their places (Fig. 163). + +The Hardwood Cutting.--Best results with cuttings of mature wood are + +Fig. 162.--OLD GERANIUM PLANT CUT BACK TO MAKE IT THROW OUT NEW SHOOTS FROM WHICH CUTTINGS CAN BE MADE. + +Fig. 163.--EARLY WINTER GERANIUM, from a spring cutting. + +BUD PROPAGATION 125 + +secured when the cuttings are made in the fall and then buried until spring in sand in the cellar. These cuttings are usually six to ten inches long. They are not idle while they rest. The lower end calluses or heals, and the roots form more readily when the cutting is planted in the spring. But if the proper season has passed, take cuttings at any time in winter, plant them in a deep box in the window, and watch. They will need no shading or special care. Grape, currant, gooseberry, willow, and poplar readily take root from the hardwood. Fig. 164 shows a current cutting. It has only one bud above the ground. + +The graft--When the cutting is inserted into a plant called a stock, it is a graft; and the graft may grow. In this case the cutting grows fast to the other plant, and the two become one. When the cutting is inserted in a plant, it is no longer called a cutting but a scion; and the plant in which it is inserted is called the stock. Fruit trees are grafted in order that a certain variety or kind may be perpetuated, as a Baldwin or Jen Bavis variety of apple, Seckel or Bartlett pear, Navel or St. Michael orange. + +Plants have preferences as to the stocks on which they will grow; but we can find out what their choice is only by making the experiment. The pear grows well on the quince, but the quince does not thrive on the pear. The pear grows on some of the hawthorns, but it is an unwilling subject on the apple. Tomato plants will grow on potato plants and potato plants on tomato plants. + +Fig. 165.--Cere- lant cutting. + +126 +**BEGINNERS' BOTANY** + +When the potato is the root, both tomatoes and potatoes may be produced, although the crop will be very small; when the tomato is the root, neither potatoes nor tomatoes will be produced. Chestnut will grow on some kinds of oak. In general, one species or kind is grafted on the same species, as apple on apple, pear on pear, orange on orange. + +The **forming**, growing tissue of the stem (on the plants we have been discussing) is the **cambium** (Casp. X), lying on the outside of the woody cylinder beneath the bark. In order that union may take place, the cambium of the scion and of the stock must come together at a point where the seam is cut on the side of the stock. There are many ways of shaping the scion and of preparing the stock to receive it. These ways are dictated largely by the relative sizes of scion and stock, although many of them are matters of personal preference. The underlying principles are two: securing close contact between the cambiaums of scion and stock; covering the wounded surfaces to prevent evaporation and to protect the parts from disease. + +On large stocks the commonest form of grafting is the **clef graft**. The stock is cut off and split; and in one or both sides a wedge-shaped scion is firmly inserted. Fig. 165 shows the scion; Fig. 166, the scions set in the stock; Fig. 167, the stock waxed. It will be seen that the lower half that lying in the wedge—is covered by the wax; but being nearest the food supply and least exposed to weather, it is the most likely to grow; it will push through the wax. + +**Clef-grafting** is practised in spring, as growth begins. The scions are cut preciously, when perfectly dormant, and from the tree which it is desired to propagate. The scions are kept in sand or moss in the cellar. Limbs of various + +BUD PROPAGATION 127 + +sizes may be eleft-grafted,—from a half inch up to four inches in diameter; but a diameter of one to one and a half inches is the most convenient size. All the leading or main branches of a tree top may be grafted. If the remaining parts of the top are gradually cut away and the sections grow well, the entire top will be changed over to the new variety. + +Fig. 85.—Scion of Apple. +Fig. 86.—The Scion Inserted. +Fig. 87.—The Pulp Waxed. + +Another form of grafting is known as budding. In this case a single bud is used, and it is slipped underneath the bark of the stock and securely tied (not waxed) with soft material, as bass bark, corn shuck, yarn, or raffia (the last a commercial palm fibre). Budding is performed when the bark of the stock will slip or peel (so that the bud can be inserted), and when the bud is moisture enough to grow. Usually budding is performed in late summer or early fall, when the winter buds are well formed; or it may be practised in spring with buds out in winter. In ordinary summer budding (waxing not being used) the "bud" or scion forms a union with the stock, and then in autumn, till the following spring, as if it were still on its own twig. + +128 +**BEGINNERS' BOTANY** + +Budding is mostly restricted to young trees in the nursery. +In the spring following the budding, the stock is cut off just above the bud, so that only the shoot from the bud grows to make the future tree. This prevailing form of budding (shield-budding) is shown in Fig. 168. + +**Secateurs.** — 128. Name the plants that the gardener propagates by means of cuttings. +129. By what season? 130. When are cuttings best made? The cutting may be set in the window. If the box does not receive direct sunlight, it may be covered with a pane of glass. In this case, however, one must take care that the air is not kept too close, else the damping-off fungi may attack the cuttings, and they will not grow well. If the box is placed in a room that has a raised little at one end to afford ventilation ; and if the water collects in drops on the under side of the glass, it will soon rot away for a time. +131. Graining wax is made of beeswax, resin, and tallow. A good recipe is one part (as much as can be held in the palm) of beeswax to two parts of tallow. +Our parts of resin; melt together in a kettle; pour the liquid into a pail or tub of water to so- +lubilize it. Then add to this liquid a little of the +"grain" or "taffy" candy, the honey being +grated when necessary. The wax will keep any length of time. For the little grating that we put on our breads and cakes, see page 57 of a seedman. +132. Graining is hardly to be recom- +mended as a general school diversion, as the in- +terest in it is very slight. The reason why this chapter is inserted chiefly to satisfy the general curiosity on the subject. 133. In Chap. V we had learned that there are two generations in "one generation" of a Griffith fruit tree, as Le Cote pear, Baldwin, or Ben Davis apple. 134. The +English apple is said to have been "originated" +by "original" 135. How is the grape propagated so as to come true in name (exhibit) +the same as its parent? 136. What are currant, +strawberry ? raspberry ? blackberry ? peach ? +pear? orange? fig? plum? cherry? apple? chest- +nut? pecan? + +Fig. 168.—Bud- +ding. The +"bud"; the +young shoot; +the +ceive u; the +budded. +The "bud"; the young shoot; the receive u; the budded. + +CHAPTER XVII +HOW PLANTS CLIMB + +We have found that plants struggle or contend for a place in which to live. Some of them become adapted to grow in the forest shade, others to grow on other plants, as epiphytes, others to climb to the light. Observe how woods grapes, and other forest climbers, spread their foliage on the very top of the forest tree, while their long flexible trunks may be bare. + +There are several ways by which plants climb, but most climbers may be classified into four groups: (1) scramblers, (2) root climbers, (3) tendril climbers, (4) twiners. + +**Scramblers.**—Some plants rise to light and air by resting their long and woody stems on the tops of bushes and quick-growing trees. These stems may be clasped in part by the growing twigs of the plants on which they recline. Such plants are scramblers. Usually they are provided with prickles or bristles. In most swedy swamp thickets, scrambling plants may be found. Briers, some roses, bedstraw or galium, bittersweet (Solanum Dulcamara, not the *Celastrus*), the tear-thumb polygonums, and other plants are familiar examples of scramblers. + +**Root Climbers.**—Some plants climb by means of true roots. These roots seek the dark places and therefore enter the chinks in walls and bark. The trumpet creeper is a familiar example (Fig. 50). The true or English ivy, which is often grown to cover buildings, is another instance. Still another is the poison ivy. Roots are + +129 + +130 +BEGINNERS' BOTANY + +distinguished from stem tendrils by their irregular or indefinite position as well as by their mode of growth. + +Tendril climbers — A slender coiling part that serves to hold a climbing plant to a support is known as a tendril. + +The free end swings or curves until it strikes some object, when it attaches itself and then coils and draws the plant close to the support. The spring of the coil also allows the plant to move in the wind, thereby enabling the plant to maintain its hold. Slowly pull a well-natured tendril from its support, and note how strongly it holds on. Watch the tendrils in a wind-storm. Usually the tendril attaches to the support by coiling about it, but the Virginia creeper and the Boston ivy (Fig. 170) attach to walls by means of disks at the ends of the tendril. + +Since both ends of the tendril are fixed, when it finds a support, the coil would tend to twist it in two. It will be found, however, that the tendril coils in different directions in different parts of its length. In Fig. 169, showing an old and stretched-out tendril, the change of direction in the coil occurred at α. In long tendrils of cucumbers and melons there may be several changes of direction. + +Tendrils may represent either branches or leaves. In the + +Fig. 169.—TENDRIL, to show where the coil is changed. + +Fig. 170.—TENDRIL OF BOSTON IVY. + +HOW PLANTS CLIMB + +131 + +Virginia creeper and the grape they are branches; they stand opposite the leaves in the position of fruit clusters, and sometimes one branch of a fruit cluster is a tendril. These tendrils are therefore homologous with fruit-clusters, and fruit clusters are branches. + +In some plants tendrils are leaflets (Chap. XI). Examples are the sweet pea and the common garden pea. In Fig. 171, observe the leaf with its two great stipules, petiole, six normal leaflets, and two or three pairs of leaflet tendrils and a terminal leaflet tendril. The cobra, a common garden climber, has a similar arrangement. In some cases tendrils are stipules, as probably in the green briers (smilax). + +The petiole or midrib may act as a tendril, as in various kinds of Clematis. In Fig. 172, the common wild Clematis or "old man vine," this mode is seen. + +Twiners.--The entire plant or shoot may wind about a support. Such a plant is a twiner. Examples are bean, hop, morning-glory, moon-flower, false bistortaceae or waxwork (Cistus), some honeysuckles, wisteria, Dutchman's pipe, dodder. The free tip of the twining branch sways about in curves, much as the tendril does, until it finds support or becomes old and rigid. + +Each kind of plant usually coils to only one direction. Most plants coil against the sun, or from the observer's left across his front to his right as he faces the plant. + +Fig. 171.--Leaves of pea. +--very large stipules, +petiole leaflets, and leaflets +supported by tendril. +131 + +132 +BEGINNERS' BOTANY + +Examples are bean, morning-glory. The hop twines from the observer's right to his left, or with the sun. + +Fig. 178. - CLEMATIS CLIMBING BY LEAF-TENDRIL. + +**Suggestions.—136.** Set the pupil to watch the behaviour of any plant that has tendrils at different stages of maturity. A vigorous cucumber plant is one of the best. Just beyond the point of a young straight tendril, a leaf will be seen to grow out. Note whether the tendril changes position from hour to hour or day to day. **137. In the tip of the tendril perfectly straight? Why? Set a young tendril on a piece of glass, with a straight tendril, and see whether the tendril will just reach it. Watch how many times it does so.** **138. If a tendril does not find a support what does it do?** **139. To test the movement of a free tendril draw an ink line lengthwise of it, and note whether this line moves up or down when the convex side is uppermost.** **140. Name the tendril-bearing plants that you know.** + +**141. Make similar observations and experiments on the tips of twining stems.** **142 What twining plants do you know, and which way do they grow? How do they get their hold? How do some shoot up?** **144 Does the stem of a climbing plant contain more or less substance (weight) than an erect self-supporting stem of the same height? Explain.** + +CHAPTER XVIII + +THE FLOWER—ITS PARTS AND FORMS + +The function of the flower is to produce seed. It is probable that all its varied forms and colours contribute to this supreme end. These forms and colours please the human fancy and add to the joy of living, but the flower exists for the good of the plant, not for the good of man. The parts of the flower are of two general kinds—those that are directly concerned in the production of seed, and those that act as covering and protecting organs. The former parts are known as the essential organs; the latter as the floral envelopes. + +Envelopes.—The floral envelopes usually bear a close resemblance to leaves. These envelopes are very commonly of two series or kinds—the outer and the inner. The outer series, known as the calyx, is usually smaller and green. It usually comprises the outer cover of the flower bud. The calyx is the lowest whorl in Fig. 173. + +The inner series, known as the corolla, is usually covered and more special than irregular in shape than the calyx. It is the showy part of the flower, as a rule. The corolla is the second or larger whorl in Fig. 173. + +The calyx may be composed of several leaves. Each leaf is a sepal. If it is of one piece, it may be lobed or divided, in which case the divisions are called calyx-lobes. + +Fig. 173.—FLOWER OF THE BUTTERFLY IN BLOOM. + +133 + +134 +**BEGINNERS' BOTANY** + +In like manner, the corolla may be composed of petals, or it may be of one piece and variously lobed. A calyx of one piece, no matter how deeply lobed, is *gamopetalous*. A corolla of one piece is *gamopetalous*. When these series are of separate pieces, as in Fig. 173, the flower is said to be *polypetalous* and *polypetalous*. Sometimes both series are of separate parts, and sometimes only one of them is so formed. + +The floral envelopes are homologous with leaves. Sepals and petals, at least when more than three are present, stand more than one wheel, and one wheel stands below another so that the parts overlap. They are borne on the expanded or thickened end of the flower stalk; this end is the *torus*. + +In Fig. 173 all the parts are seen as attached to the torus. This part is sometimes called the *receptacle*, but this word is a common-language term of several meanings, whereas torus has no other meaning. Sometimes one part is attached to another part, as in the fuchsia (Fig. 174), in which the petals are borne on the calyx-tube. + +**Subtending Parts.** — Sometimes there are leaf-like parts just below the calyx, looking like a second calyx. Such parts accompany the carnation flower. These parts are bracts (bracts are small specialized leaves); and they form an involucre. We must be careful that we do not mistake them for true flower parts. Sometimes the bracts are large and petal-like, as in the great white blooms of the + +Fig. 173.—Flower of Fuchsia in section. + +THE FLOWER—ITS PARTS AND FORMS + +135 + +flowering dogwood: here the real flowers are several, small and greenish, forming a small cluster in the centre. + +**Essential Organs.** —The essential organs are of two types. The outer series is composed of the *stamens*. The inner series is composed of the *pistils*. + +*Stamens bear the pollen*, which is made up of grains or spores, each spore usually being a single plant cell. The stamen is of two parts, as is readily seen in Figs. 173, 174,—the enlarged terminal part or *anther*, and the stalk or *filament*. The filament is often so short as to seem to be absent, and the anther is then said to be *sessile*. The anther bears the pollen spores. It is made up of two or four parts (known as sperangia or spore-cases), which burst and discharge the pollen. When the filaments are shed, the stamens die. + +The *pistil has three parts*: the lowest, or seed-bearing part, which is the *ovary*; the *stigma* at the upper extremity, which is a flattened or expanded surface, and usually rounded or sticky; the stalk-like part or *style*, connecting the ovary and the stigma. + +Sometimes the style is apparently wanting, and the stigma is said to be sessile on the ovary. These parts are shown in the fleshy (Fig. 174). The ovary or seed vessel is at a. A long style with a large stigma, projects from the flower-stalk (Fig. 175 and 176). + +Stamens and pistils probably are homologous with leaves. A *pistil* is sometimes conceived to represent anciently a + +A diagram showing the structure of a flower bud. +175—THE STRUCTURE OF A FLUSH BUD. + +at., sepals; p., petal; sta., stigma; o., ovary; s., style; t., stigma; e., end of ovary; e., ovary; s., style and the stigma. It contains the seed pod. The seed case is called a fruit, but when the pollen has been shed, the ovary is ripened into the fruit. + +176—A FLOWERING PLANT WITH A LONG STYLA AND LARGE STIGMA. + +136 +BEGINNERS' BOTANY + +leaf as if rolled into a tube; and an anther, a leaf of which the edges may have been turned in on the midrib. + +The pistil may be of one part or com- +partment, or of many parts. The different +units or parts of which it is composed are +carpels. Each carpel is homologous with +a leaf. Each carpel bears one or more +seeds. A pistil of one carpel is simple; +of two or more carpels, compound. Usu- +ally the structure of the pistil may be de- +termined by cutting horizontally across the lower or seed- +bearing part, as Figs. 177, 178 explain. A flower may +contain a simple pistil (one carpel), as +the pen (Fig. 177); several simple pis- +tils (several carpels), as the buttercup (Fig. 170); or a compound +pistil with carpels united, as the Saint +John's Wort (Fig. 178) and apple. How +many carpels in an apple? A peach? +An okra pod? A bean pod? The seed cavity in each carpel is called a +locale (Latin locus, a place). In these +locules the seeds are borne. + +Conformation of the Flower. — A +flower that has calyx, corolla, stamens, +and pistil is said to be complete (Fig. +173); all others are incomplete. In some flowers both the floral envelopes are wanting; such are naked. When +one of the floral envelope series is +wanting, the remaining series is said +to be ciliate, and the flower is therefore +apetalous (without petals). The knot- +Figs. 176.—Simple +Pistil of a Spon- +terculum. +Figs. 177, 178.—Pistil of +Garden Pea, the +carpel being cut down in order to dis- +close it; also a section showing the single +compartiment (compare Fig. 18). +Figs. 179.—Compound +Pistil of a Saint +John's Wort. It has +5 carpels. + +A diagram showing a flower with five separate petals. + +Figs. 180, 181.—Compound Pistil of a Plantain. + +THE FLOWER--ITS PARTS AND FORMS 137 + +wood (Fig. 179), smartweed, buckwheat, elm are examples. + +Some flowers lack the pistils: these are *stamine*, whether the envelopes are missing or not. Others lack the stamens: these are *pistillate*. Others have neither stamens nor pistils: these are *sterile* (snowball and hydrangean). Those that have both stamens and pistils are *perfect*, whether or not the envelopes are missing. + +Those that lack either stamens or pistils are *imperfect* or *diclinous*. + +Stamine and pistillate flowers are imperfect or diclinous. + +When stamineate and pistillate flowers of the same plant, e.g., oak (Fig. 180), corn, beech, chestnut, hazel, walnut, hickory, pine, begonia (Fig. 181), watermelon, + +A small illustration showing a flower with two stamens and one pistil. +B A small illustration showing a flower with one stamen and one pistil. + +139—KNOTWEED, a very common but inconspicuous plant along hard walks and roads. Two flowers, enlaged, are shown at the right. These flowers are very small and borne in the axils of the leaves. + +140—STAMINATE CATKIN OF OAK. The pistillate flowers are at the left side, and not shown in this pic- +ture. + +141—BEGONIA FLOWERS. +Stamineate at A; pistillate at B; winged ovary at B. + +An illustration of a begonia flower with stamens and pistil. +An illustration of a begonia flower with only one pistil. + +138 + +**BEGINNERS' BOTANY** + +gourd, pumpkin, the plant is *monocious* ("in one house") When they are on different plants, e.g. papaw, cottonwood, bois d'arc, willow (Fig. 182), the plant is *dioecious* ("in two houses"). Some varieties of strawberry, grape, and mulberry are partly dioecious. Is the rose either monocious or dioecious? + +Flowers in which the parts of each series are alike are said to be regular (as in Figs. 173, 174, 175). Those in which some parts are unlike other parts of the same series are irregular. Their regularity may be in calyx, as in nasturtium (Fig. 183); in corolla (Figs. 184, 185); in the stamens (compare nasturtium, catnip, Fig. 185, sago); in the pistils. Irregularity is most frequent in the corolla. + +Fig. 182.—CATKINS OF A WILLOW. +A staminate flower is shown at a, and a pistillate flower at b. The stamens and pistillae are on different plants. + +Fig. 183.—FLOWER OF GARDEN NASTURTIUM. +Separate pistil at a. The calyx is produced into a spat. + +Fig. 184.—THE FIVE PETALS OF THE FLOWERY, detached to show the form. +The five petals of the nasturtium are shown at b. + +Fig. 185.—FLOWER OF CATNIP. +The stamens of catnip are shown at c. + +THE FLOWER--ITS PARTS AND FORMS 139 + +Various Forms of Corolla.--The corolla often assumes very definite or distinct forms, especially when gamopetalous. It may have a long tube with a wide-flaring limb, when it is said to be funnel-form, as in morning-glory and pumpkin. If the tube is very narrow and the limb stands at right angles to it, the corolla is salver-form, as in phlox. If the tube is very short and the limb wide-spreading and nearly circular in outline, the corolla is rotate or wheel-shaped, as in potato. + +A gamopetalous corolla or gamopetalous calyx is often cleft in such way as to make two prominent parts. Such parts are said to be lipped or labiate. Each of the lips or lobes may be notched or toothed. In 5-membered flowers, the lower lip is usually 3-lobed and the upper one 3-lobed. Labiate flowers are characteristic of the mint family (Fig. 183), and the family therefore is called the Labiatae. (Labi-, labia, "lipped," without specifying the manner of lips or lobes; but it is commonly used to designate 2-lipped flowers.) Strongly 2-parted polypetalous flowers may be said to be labiate; but the term is often used for gamopetalous co-rolas. + +Labiate gamopetalous flowers that are closed in the throat (or entrance to the tube) are said to be grinning or personate (per-sonate means *ansel*). Snapdragon is a typical example; also *oadfax* or butter-and-eggs (Fig. 186), and many related plants. Personate flowers usually have definite relations to insect pollination. Observe how an insect forces its head into the closed throat of the *oad-fax*. + +Fig. 185.--PERSONATE FLOWER OF TOAD-FAX. + +140 +BEGINNERS' ROTANY + +The peculiar flowers of the pea tribes are explained in Figs. 187, 188. + +**Spathic Flowers.** — In many plants, very simple (often naked) flowers are borne in dense, more or less fleshy spikes, and the spike is enclosed in or attended by a leaf, sometimes corolla-like, known as a *spatha*. The spike of flowers is technically known as a *spadix*. This type of flower is characteristic of the great arum family, which is + +d + +Fig. 187.—Flowers of the **Comos Bean**, with one flower opened (a) to show the structure. + +chiefly tropical. The commonest wild representatives are Jack-in-the-pulpit, or Indian turnip, and skunk cabbage. In the former the flowers are all diclinous and naked. In the skunk cabbage all the flowers are perfect and have four sepals. The common calla is a good example of this type of inflorescence. + +**Composite Flowers.** — The head (anthelmion) or so-called "flower" of sunflower (Fig. 189), thistle, aster, dandelion, daisy, chrysanthemum, goldenrod, is composed of several or many little flowers, or *florets*. These + +c +b +a +d + +Fig. 188.—Diagram of Alfalfa Flower (in section). + +C, calyx; D, standard; P, sepal; E, petal; T, staminate; F, filament of staminate stamen; X, pistil; Y, pistil with stigma; Z, ovary; A, base position of staminate tube, when pushed upward by nectar. + +THE FLOWER--ITS PARTS AND FORMS + +141 + +florets are enclosed in a more or less dense and usually green involucre. In the thistle (Fig. 190) this involucre is prickly. A longitudinal section discloses the florets, all attached at bottom to a common torus, and densely packed in the involucre. The pink tips of these florets constitute the showy part of the head. + +Each floret of the thistle (Fig. 190) is a complete flower. At $a$ is the ovary. At $b$ is a much-divided plumy calyx, known as the pappus. The corolla is long tube, rising above the pappus, and is enlarged and lobed over the top, or $c$. The style projects from $d$. The stamens are united about the style in a ring at $d$. Such anthers are said to be syngenesious. These are the various parts of the florets of the Composite. In some cases the pappus is in the form of barbs, bristles, or scales, and sometimes it is wanting. The pappus, as we shall see later, assists in distributing the seed. Often the florets are not alike. The corolla of those in the outer circles may be developed into a long straplike or tubular part, and the head then has the ap- + +Fig. 189.--HEAD OF SUNFLOWER. +Fig. 190.--LONGITUDINAL SECTION OF THISTLE HEAD; also a FLORET OF THISTLE. + +142 +**BEGINNERS' BOTANY** + +pearance of being one flower with a border of petals. Of such is the sunflower (Fig. 180), aster, bachelor's button or cornflower, and field daisy (Fig. 211). These long-calyxed are called rays. In some cultivated composites, all the florets may develop rays, as in the dahlia and the erythranthum. In some species, as dandelion, all the florets naturally have rays. Syngenesious arrangement of anthers is the most characteristic single feature of the composites. + +**Double Flowers.** — Under the stimulus of cultivation and increased food supply, flowers tend to become double. True doubling arises in two ways, morphologically: (1) stamens may produce petals (Fig. 191); (2) adventitious or accessory petals may arise in the circle of petals. Both these categories may be present in the same flower. In the full double hollyhock the petals derived from the staminal column are shorter and make a rosette in the centre of the flower. In Fig. 192 is shown the doubling of a daffodil by the modification of stamens. Other modifications of flowers are sometimes known as doubling. For example, double dahlias, chrysanthemums, and sunflowers are forms in which the club flowers have developed rays. The snowball is another case. In the wild snowball the external flowers of the cluster are large and sterile. In the culti- +Fig. 191.—Petals arising from the staminal column of Hollyhock, and accessory petals in the conical head. + +double hollyhock the petals derived from the staminal column are shorter and make a rosette in the centre of the flower. In Fig. 192 is shown the doubling of a daffodil by the modification of stamens. Other modifications of flowers are sometimes known as doubling. For example, double dahlias, chrysanthemums, and sunflowers are forms in which the club flowers have developed rays. The snowball is another case. In the wild snowball the external flowers of the cluster are large and sterile. In the culti- + +THE FLOWER—ITS PARTS AND FORMS + +143 + +vated plant all the flowers have become large and sterile. +Hydrangea is a similar case. + +Fig. 153. AERANTHUS. Single flower to the right. +SUGGESTION.—145. If the pupil has been actively conducted through this chapter by means of careful study of specimens rather than as a mere memorizing process, he will be in mood to chal- +lenge any one who may ask him to name a flower he has not seen it. Flowers are endlessly modified in form; but they can be understood if the pupil looks first at the anthers and ovaries. Have not many flowers that have been named, e.g., lily, iris, excellent practice to find the flowers in plants that are commonly known by name, and to determine the main points in their structure. +What is the flower of the following?






































































+
    +
  1. Celery ? cabbage ? potato ? pea ? tomato ? okra ? cotton ? rhubarb?
    2. +
  2. Cherries ? peaches ? oats ? 147. Do all forest trees have flowers?
    3. +
+Explain. +148. The names of flowers are often derived from other words. Know. +Directions. 149. What plants do you know that bloom before the leaves appear? Do any blossoms after the leaves fall? 150. Ex- +plain the difference between morgage, lily-of-the-valley, ivy, asparagus, +garlic bulbs, sunflowers, orchid, lily-of-the-valley, crocus, Golden Glow, mulberries, cowpeas. 151. Define a flower. + +NOTE TO THE TEACHER.—It cannot be urged too often that the specimen themselves should be used as much as possible. When once become a mere memorizing process and definitions, the exercise will be worse than useless. Properly taught by means of the flowers themselves, the names become merely incidental and a part of the pupil's language, and the subject has living interest. + +Fig. 153. AERANTHUS. Single flower to the right. + +CHAPTER XIX + +THE FLOWER—FERTILIZATION AND POLLINATION + +Fertilization.—Seeds result from the union of two elements or parts. One of these elements is a cell-nucleus of the pollen-grain. The other element is the cell-nucleus of an egg-cell, borne in the ovary. The pollen-grain falls on the stigma (Fig. 193). It absorbs the juices exuded by the stigma, and grows by sending out a tube (Fig. 194). This tube grows downwards through the style, absorbing food as it goes, and finally reaches the egg-cell in the interior of an ovule in the ovary (Fig. 195). In fertilization, or union of a nucleus of the pollen and the nucleus of the egg-cell in the ovule, takes place. + +The ovule and embryo within then develops into a seed. The growth of the pollen-tube is often spoken as germination of the pollen, but it is not germination in the sense in which the word is used when speaking of seeds. + +Better seeds—that is, those that produce stronger and more fruitful plants—are often re-sult when the pollen comes from another flower. Fertilization effected between different flowers is cross-fertilization; that resulting from the + +Fig. 193.—A POLLEN-GRAIN ESCAPING FROM ANTHOR; A POLLEN-GRANULE ON THE STIGMA. +Enlarged. + +Fig. 194.—A POLLEN-GRAIN AND ITS GROWING TUBE. + +144 + +THE FLOWER—FERTILIZATION AND POLLINATION 145 + +application of pollen to pistils in the same flower is close-fertilization or self-fertilization. It will be seen that the cross-fertilization relationship may be of many degrees—between two flowers in the same cluster, between those in different clusters on the same branch, between those on different plants. Usually fertilization takes place only between plants of the same species or kind. + +In many cases this is, in effect, an application of pollen when pollen from two or more sources is applied to the stigma. Sometimes the foreign pollen, if from the same kind of plant, grows, and fertilization results, while pollen from the same flower is less promptly effective. If, however, no foreign pollen is present, the pollen from the same flower may finally serve the same purpose. + +In order that the pollen may grow, the stigma must be ripe. At this stage the stigma is usually moist and sometimes sticky. A ripe stigma is said to be receptive. The stigma may remain receptive for several hours or even days, depending on the kind of plant, the weather, and how soon pollen is received. Watch a certain flower every day to see the anther lobules open and the stigma ripen. When fertilization takes place, the stigma dies. Observe, also, how soon the petals wither after the stigma has received pollen. + +Pollination—The transfer of the pollen from one anther to stigma is known as pollination. The pollen may + + +A diagram to represent fertilization. + +Diagram showing a flower with stamen (st) and pistil (pt). The stamen has a filament (f) and an anther (a), which contains pollen grains (pg). The pistil has a style (s) leading to a stigma (stigma). + + + +146 +**BEGINNERS' BOTANY** + +fall of its own weight on the adjacent stigma, or it may be carried from flower to flower by wind, insects, or other agents. There may be self-pollination or cross-pol- +lination, and of course it must always precede fertilization. + +Usually the pollen is discharged by the burst- +ing of the anthers. The commonest method of +discharge is through a slit on either side of the anther (Fig. 193). Sometimes it discharges +through a pore at the apex, as in azalea (Fig. +196), rhododendron, huckleberry, wintergreen, +in some plants a part of the anther wall raises +or falls as a lid, as in barberry (Fig. 197), blue +cohosh, May apple. The opening of an anther +(as also of a seed pod) is known as dehiscence (de, from ; +Latin, open). When an anther or seed pod opens, it is said to dehisce. + +Most flowers are so constructed as to increase the chances +of cross-pollination. We have seen that the stigma may +have the power of choosing foreign pollen. The +commonest means of necessitating cross-polli-na- +tion is the different times of maturing of stamens +and pistils in the same flower. In most cases +the stamens mature first: the flower is then +proterandrous. When the pistils mature first, +the flower is protogynous. (*Auer, aude, is a Greek root often used, in combinations, for +sten- men, and grue for pistil.) The difference in +time of ripening may be an hour or two, or it +may be a day. The ripening of the stamens +and the pistils at different times is known as dichogamy, and +flowers of such character are said to be dichogamous. +There is little chance for dichogamous flowers to pollinate themselves. Many flowers are imperfectly dichogamous— + +A diagram showing the structure of a flower with stamens and pistils. + +Fig. 196.— +ANThER OF AzALEA. +opening by terminal pores. + +Fig. 197.— +BarBERRY. +STAMENS and pistils opening by lid. + +Fig. 198.— +HUCKLEBERRY. +STAMENS and pistils opening by lid. + +THE FLOWER—FERTILIZATION AND POLLINATION 147 + +some of the anthers mature simultaneously with the pistils, so that there is chance for self-pollination in case foreign pollen does not arrive. Even when the stigma receives pollen from its own flower, cross-fertilization may result. The hollyhock is pentamerous (Fig. 198) shows a flower recently expanded. The stamens in Fig. 199, showing an older flower, the long styles are conspicuous. + +Some flowers are so constructed as to prohibit self-pollination. Very irregular flowers are usually of this kind. +With some of them, the petals form a sac to enclose the anthers and the pollen cannot be shed on the stigma but is retained until a bee forces the sac open; the pollen is rubbed on the hairs of the bee and transported. + +Regular flowers usually depend mostly on dichogamy and the selective power of the pistil to insure crossing. Flowers that are very + +Fig. 198.—FLOWER OF HOLLYHOCK ; pentamerous. +Fig. 198.—FLOWER OF HOLLYHOCK ; pentamerous. + +Fig. 199.—OLDER FLOWER OF HOLLYHOCK. +Fig. 199.—OLDER FLOWER OF HOLLYHOCK. + +148 + +irregular and provided with nectar and strong perfume are usually pollinated by insects. Gaudy colours probably attract insects in many cases, but perfume appears to be a greater attraction. + +The insect visits the flower for the nectar (for the making of honey) and may unknowingly carry the pollen. Spurs and sacs in the flower are nectaries (Fig. 200), but in sparsely flowers the nectar is usually secreted in the bottom of the flower cup. This compels the insect to visit by the side and rubs against the pollen before it reaches the nectar. Sometimes the anther is a long lever poised on the middle point and the insect bamps against one end and lifts it, thus bringing the other end of the lever with the pollen sacs down on its back. Flowers that are pollinated by insects are said to be **entomophilous** ('insect lov-ing'). Fig. 200 shows a larkspur. + +The envelopes are separated in Fig. 201. The long spur at once suggests insect pollination. The spur is a sepal. Two hollow petals project into this spur, apparently serving to guide the bee's tongue. The two smaller petals, in front, are peculiarly coloured and perhaps serve the bee in locating the nectary. The stamens behind, the pistils (Fig. 202). As the insect stands on the flower and thrusts its head into the centre, + +Fig. 200.--FLOWER OF LARKSPUR. +**Fig. 200.--FLOWER OF LARKSPUR.** + +Fig. 201.--ENVELOPES OF A LARKSPUR, showing how they are separated, the upper one being opened. +**Fig. 201.--ENVELOPES OF A LARKSPUR, showing how they are separated, the upper one being opened.** + +There are four petals in this flower, two large ones in front and two small ones behind. The two large ones are called **petaloid sepals**, because they resemble petals in shape and colour, while the two small ones are called **staminodes**, because they resemble stamens in shape and colour. + +THE FLOWER—FERTILIZATION AND POLLINATION 149 + +the envelopes are pushed downward and outward and the pistil and stamens come in contact with its abdomen. +Since the flower is protandrous, the pollen that the pistils receive from the bee's abdomen must come from another flower. Note a somewhat similar arrange-ment in the toadflax or butter-and-eggs. + +In some cases (Fig. 203) the stamens are longer than the pistil on one flower and shorter in another. If the insect visits two flowers, it gets pollen on its head from the long-stamen flower, and deposits this pollen on the stigma in the long-pistil flower. Such flowers are di-morphic (of two forms). If pollen from its own flower and from another flower both fall on the stigma, the proba-bilities are that the stigma will choose the foreign pollen. + +Fig. 202.—STAMENS OF LANTANA, sur-rounding the pistil. + +Fig. 203.—DI-MORPHIC FLOWERS OF PRIMROSE. +Many flowers are pollinated by the wind. They are said to be anemophilous ("wind loving"). Such flowers pro- + +duce great quantities of pollen, for much of it is wasted. +They usually have broad stigmas, which expose large surfaces to the wind. They are usually lacking in gaudy colours and in perfume. Grasses and pine trees are typical examples of ameophytes. + +In many cases cross-pollination is assured because the stamens and the pistils are in different flowers (diocious). + +Monocious and dioecious plants may be pollinated by wind or insects. The oats are dioecious (Fig. 204). They are usually wind-pollinated, although willows are often, if not mostly, insect-pollinated. The Indian corn is a monocious plant. + +The stamine flowers arc in a terminal panicle (tassel). The pistillate flowers are in a dense spike (ear), enclosed in a sheath or husk. Each "silk" is a style. Each pistillate flower produces a kernel of corn. Sometimes a few pistillate flowers are borne in the tassel and a few stamine flowers on the tip of the ear. Is self-fertilization possible with the corn? Why does a "volunteer" stalk standing alone in a garden have only a few grains on the ear? What is the direction of the prevailing wind in summer? If only two or three rows of corn are + + +A diagram showing the structure of a corn plant, including the tassel (stamine flowers) and the ear (pistillate flowers). + + +**FIG. 204.—FLOWERS OF BLACK WALNUT; TWO PIECES OF FLOWERS OF OATS AND STAMINATE CANKS OF CORN.** +150 + +THE FLOWER--FERTILIZATION AND POLLINATION 151 + +planted in a garden where prevailing winds occur, in which direction had they better run? + +Although most flowers are of such character as to insure or increase the chances of cross-pollination, there are some that absolutely forbid crossing. These flowers are usually borne beneath or on the ground, and they lack showy colours and perfumes. They are known as cleistogamous flowers (meaning self-fertilizing flowers). The plant has normal showy flowers that may be insect-pollinated, and in addition is provided with these simplified flowers. Only a few of these are cleis- +togamous flowers. Hops, peanut, common blue violet, frigid winter-green, and dalibarda are the best subjects in this country. Fig. 205 shows a cleistogamous flower of the blue violet at A. Above the true roots, slender stems bear these flowers, that are provided with a calyx, and a curving corolla which does not open. Inside are the stamens and the pistils. Late in the season the cleistogamous flowers may be found just underneath the mould. They never grow above ground. The following summer one may find a seedling plant, in + +Fig. 205.--COMMON BLUE VIOLET. The familiar flowers are shown, natural size. The smaller flowers, which are common cleistogamous flowers are often borne on the surface of the ground. A small one is shown at B. Another one is shown at C. Both A and C are one third natural size. + +151 + +152 +BEGINNERS' BOTANY + +some kinds of plants, with the remains of the old cleistogamous flower still adhering to the root. Cleistogamous flowers usually appear after the showy flowers have passed. They seem to insure a crop of seed by a method that expends little of the plant's energy. The pupil will be interested to work out the fruiting of the peanut (Fig. 206). Unhaked fresh specimens grow readily and can easily be raised in Canada, in a warm sandy garden. + +SUGGESTIONS.--- + +**152** Not all the flowers produce seeds. Note that apple trees may bloom very full, but that only reliable pollen is needed to fertilize the flowers; this increases the chances that sufficient + +A diagram showing the process of peanut ripening underground. +FIG. 206. - FOES OF PEANUT RIPENING UNDERGROUND. + +A diagram showing apple blossoms and leaves. +FIG. 207. - STRUGGLE FOR EXISTENCE AMONG THE APPLE FLOWERS. + +may result (Fig. 207). More pollen is produced than is needed to fertilize the flowers; this increases the chances that sufficient + +THE FLOWER—FERTILIZATION AND POLLINATION + +stigmas will receive acceptable pollen to enable the plant to perpetuate its kind. At any time in summer, or even in fall, examine the apple trees carefully to determine whether any dead flowers have been left on them. In the same way examine any full-blooming plant to see whether any of the flowers fail. +153. Keep watch on any plant to see whether insects visit it. The bees are the most important pollinators, but ants, flies, and other insects also visit the calyx serves any purpose in protecting the flower. Very carefully remove the calyx from a bud that is normally exposed to heat and notice what effect this has upon the appearance of the others. +155. Cover a single flower on its plant with a tiny paper or muslin bag so tightly that no insect can get in. If the flower is covered by a muslin bag, it will not be fertilized. Remove the corolla from a flower nearly ready to open, preferably one that has no other flowers very close to it. Watch for insects. 157. Find the insect in any weather and place it near the flower stigma. +Wheat, oats, barley, 159. Which of the following plants have perfect flowers: pea, bean, pumpkin, cotton, clover, buckwheat, potato, Indian corn, peach, chestnut, hickory, watermelon, sunflower, cab- bage, tobacco, poplar, apple, cherry, plum, pear, maple, oaks, +wood, catalpa? What have the others? 160. On wind- +pollinated plants, are either anthers or stigmas more numerous? +161. How many anthers does each flower of a daisy have in clusters? +162. Why do rain at blooming time often beset +the fruit crop? 163. Of what value are bees in orchards? 164. What is meant by "self-pollination"? 165. What new varieties - It may be desired to perform the operation of polli- +nation by hand. In order to insure the most definite results, evaporation of moisture must be prevented during which it is desired shall be used, and rapidly to exclude all other pollen. +(a) The first requisite is to remove the anthers from the flower when they are fully developed and before they begin to shed their pollen. +The flower-bud is therefore opened and the anthers taken out. Cut off the floral envelopes with small, sharp-pointed scissors, carver or knife. The anthers are then only the tips of these are merely opened the corolla at the end and pull out the anthers with a hook or tweezers; and this method is often the best one. It is best to detach the operation as long as possible after opening the bud (so that no pollen may escape from the flower to foreign pollen) nor the anthers to discharge the pollen. +(b) The flowers must next be covered with a paper bag to prevent their being visited by insects until they are not receptive at the time (as it usually is), the desired pollen is not applied at once. +The bag may be removed from time to time to allow of examination of the pistil and when the stigma is mature which is told by its globose or rounded appearance, +153 + +154 +BEGINNERS' BOTANY + +the time for pollination has come. If the bag is slightly moistened, it can be puckered more tightly about the stem of the plant. The time required for the stigmas to mature varies from several hours to several days, according to the species. The stigmas are usually removed from the desired flower by crushing on the finger nail or a knife blade, and the pollen is rubbed on the stigma by means of a tiny brush, the point of a knife blade, or a sliver of wood. The + +A paper bag with string inserted. +Fig. 208.—A Paper Bag, +with string inserted. + +The bag tied over a flower. +Fig. 209.—The Bag Tied +OVER A FLOWER. + +flower is again covered with the bag, which is allowed to remain for several days until all attempts at other pollination is made. Care must be taken that no dust or other foreign matter comes into contact with the stigma, and that no pollen falls upon it, if possible. The seeds produced by a crossed flower produce hybrids, or plants having parents belonging to different varieties. The best way of breeding new forms of plants is by making hybrids. Why? + +The fig is a hybrid tree with flowers borne on the inside, and pollinated by insects that eat out of the fruit. +Fig. 210.—The fig is a hybrid tree with flowers borne on the inside, and pollinated by insects that eat out of the fruit. + +CHAPTER XX + +FLOWER-CLUSTERS + +Origin of the Flower-cluster.---We have seen that branches arise from the axils of leaves. Sometimes the leaves may be reduced to bracts, and yet branches are borne in them. In some cases the branches grow into long limbs; others become short spurs; others bear flowers. In fact, a flower is itself a specialized branch. + +Flowers are usually borne near the top of the plant. Often they are produced in great numbers. It results, therefore, that flower branches usually stand close together, forming a cluster. The shape and the arrangement of the flower-cluster differ with the kind of plant, since each plant has its own mode of branching. + +Certain definite or well-marked types of flower-clusters have received names. Some of these names will fall within this chapter, but the flower-clusters that perfectly match the definitions are the exception rather than the rule. + +The determining of the + +Fig. 211. - Terminal flowers of a daisy (Bellis perennis), showing the flower placed on eye-daisy). + +35 + +136 +BEGINNERS' BOTANY + +kinds of flower-clusters is one of the most perplexing sub- +jects in descriptive botany. We may classify the subject +around three ideas: solitary flowers, centrifugal or deter- +minate clusters, centripetal or indeterminate clusters. + +Solitary Flowers. — In many cases flowers are borne +singly; they are separated from other flowers by leaves. +They are then said to be solitary. The solitary flower may +be either at the end of the main shoot or axis (Fig. 211), +when it is said to be terminal; or from the side of the shoot +(Fig. 212), when it is said to be lateral or axillary. + +Centripetal Clusters. — If the flower-bearing axils are +rather close together, an open or leafy flower-cluster might +result. If the plant continues to grow from the tip, the +older flowers are left farther and farther behind. The +cluster thus shows as to be +LATERAL FLOWER OF AN ANTHESIS, a greenhouse plant. +centripetal. The younger ones, too, cut +earmer flowers would be the +older. A flower-cluster in which the lower or outer flowers +open first is said to be a centripetal cluster. It is some- +times said to be an indeterminate cluster, since it is the +result of a type of growth which may go on more or less +continuously from the apex. + +The simplest form of a definite centripetal cluster is a +raceme, which is an open elongated cluster in which the +flowers are borne singly on very short branches and open +from below (that is, from the older part of the shoot). + +FLOWER-CLUSTERS 157 + +upwards (Fig. 213). The raceme may be terminal to the main branch; or it may be lateral to it, as in Fig. 214. +Racemes often bear the flowers on one side of the stem, thus forming a single row. +When a cen- +tripetal flower-cluster is long and dense and the flowers are sessile or nearly so, it is called a spike (Fig. 215). Common examples of spikes are plantain, mignonette, mullein. +A very short and dense spike is a head. Clover (Fig. 216) is a good example. The sunflower and related plants bear many small flowers in a very dense and often flat head. Note that in the sunflower (Fig. 189) the outside or exterior flowers + +Fig. 213.—RACEME OF CURCUMA. +TEXT OF FLANTAIK + +Fig. 214.—LATERAL RACEMES (in fig.) OF BARBERETT. + +158 +BEGINNERS' BOTANY + +open first. Another special form of spike is the **catkin**, which usually has scaly bracts, the whole cluster being deciduous after flowering or fruiting, and the flowers (in typical cases) having only stamens or pistils. Examples are the "pussies" of willows (Fig. 182) and flower-clusters of oak (Fig. 180), walnuts (Fig. 204), poplars. + +A flower cluster with multiple small flowers. + +**Fig. 276.—HEAD OF CLO-VER BLOSSOMS.** + +When a loose, elongated centralpetal flower-cluster has some primary branches simple, and others irregularly branched, it is called a **panicle**. It is a branching raceme. Because of the earlier growth of the lower branches, the panicle is usually broadest at the base or conical in outline. True panicles are not very common. + +**Fig. 277.—CORYNE OF CANDELTREE.** + +When an indeterminate flower-cluster is short, so that + +FLOWER-CLUSTERS 159 + +the top is convex or flat, it is a *corymb* (Fig. 217). The outermost flowers open first. Centripetal flower-clusters are sometimes said to be corymbose in mode. + +When the branches of an indeterminate cluster arise from a common point, like the frame of an umbrella, the cluster is an *umbel* (Fig. 218). Typical umbels occur in carrot, parsnip, caraway, and other plants of the parsley family: the family is known as the Umbelliferae, or umbel-bearing + +Fig. 218. - REMAINS OF A LAST YEAR'S UMBEL OF WILD CARROT. +family. In the carrot and many other Umbelliferae, there are small or secondary umbels, called *umbellets*, at the end of each of the main branches. (In the stem of the wild carrot umbel one often finds a single, blackish, often aborted flower, comprising a 1-flowered umbellet.) + +Centrifugal or Determinate Clusters—When the terminal or central flower opens first, the cluster is said to be centrifugal. The growth of the shoot or cluster is determinate, since the length is definitely determined or stopped by the terminal flower. Fig. 219 shows a determinate or centrifugal mode of flower bearing. + +160 + +**BEGINNINGS** BOTANY + +Dense centrifugal clusters are usually flatish on top because of the cessation of growth in the main central axis. These compact flower-clusters are known as cymes. Centrifugal clusters are sometimes said to be cymose in mode. Apples, pears (Fig. 220), and elders bear flowers in cymes. Some cyme-forms are like umbels in general appearance. A head-like cymose cluster is a *glomerule*; it blooms from the top downwards rather than from the base upwards. + +**Mixed Clusters.** — Often the cluster is mixed, being determinate in one part and indeterminate in another part of the same cluster. The cluster has the appearance of a panicle, and is usually so called, but it is really a *thryse*. + +Lilac is a familiar example of a thyrse. In some cases the main cluster is determinate and the branches are indeterminate, as in hydrangeas and elders. + +**Inflorescence.** — The mode or method of flower arrangement is known as the **inflorescence**. That is, the inflorescence is cymose, corymbose, paniculate, spicate, solitary, determinate, indeterminate. By custom, however, the word "inflorescence" + +Fig. 219.—DETERMINATE OR CYMOE ARRANGEMENT.—Wild geranium. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 220.—CYME OF PEAR. +Fig. 219—DETERMINATE OR CYMOE ARRANGEMENT—Wild geranium
+ +FLOWER-CLUSTERS + +161 + +Fig. 221. — Forms of Centripetal Flower-clusters. +1, raceme; 2, spicule; 3, umbel; 4, head or inflorescence; 5, corymb. + +Fig. 222. — CENTRIPETAL INFLORESCENCE, continued. +6, umbel; 7, compound umbel; 8, corymb. + +Fig. 223. — CENTRIPETAL INFLORESCENCE. +1, cyme; 2, scapoid raceme (or half cyme). + +A diagram showing different forms of centripetal flower clusters. + +162 +BEGINNERS' BOTANY + +has come to be used in works on descriptive botany for the flower-cluster itself. Thus a cyme or a panicle may be called an inflorescence. It will be seen that even solitary flowers follow either indeterminate or determinate methods of branching. + +The flower-stem. — The stem of a solitary flower is known as a peduncle; also the general stem of a flower-cluster. The stem of the individual flower in a cluster is a pedicel. In the so-called stemless plants the peduncle may arise directly from the ground, or crown of the plant, as in dandelion, hyacinth, garden daisy; this kind of peduncle is called a scape. A scape may bear one or many flowers. It has no foliage leaves, but it may have bracts. + +Sectiores. — 165. Name six columns in your notebook as follows: (a) Cyme; (b) Panicle; (c) Cyme; (d) Cluster. Write each of the following in its appropriate column: thistle, grey-rose, wataria, onion, bridal wreath, bananas, hydrangeas, phlox, China berry, fly-of-the-willow, Spanish dagger (or yucca), sorghum, interior poplar, larkspur, hawthorn, hollyhock, mullein, crpe myrtle, locust, narcissus, snapdragon, peppermint, shepherd's purse, couch-grass, wheat, hawthorn, geranium, carrot, elder, dandelion. Note that some of these are found in your region that do not grow in your region. 167. In the study of flower-clusters, it is well to choose first those that are fairly typical of the various types. For example, in the cyme and panicle clusters you see as the main types are well fixed in the mind, random clusters should be examined, for the pupil must never receive the impres-sion that all clusters are alike. The clusters of some of the commonest plants are very puzzling, but the pupil should at least be able to discover whether the inflorescence is determinate or indeterminate. Figures 221 to 223 illustrate the theoretical analysis of inflorescences. The numerals indicate the number of species. + +A diagram illustrating the theoretical analysis of inflorescences. + +CHAPTER XXI + +FRUITS + +The ripened ovary, with its attachments, is known as the fruit. It contains the seeds. If the pistil is simple, or of one carpel, the fruit also will have one compartment. If the pistil is compound, or of more than one carpel, the fruit usually has an equal number of compartments. The compartments in pistil and fruit are known as la- +224cules (from Latin locus, meaning "place.") + +The simplest kind of fruit is a ripened 1-located ovary. The first stage in complex- +ity is a ripened 2- or many-located ovary. Very complex forms may arise by the attachment of other parts to the ovary. Sometimes the style persists and becomes a beak (mustard pods, dentaria, Fig. 224), or a tail in clematis; or the calyx may be attached to the ovary; or the ovary may be embedded in the receptacle, and ovary and receptacle together constitute the fruit; or an involucre may become a part of the + +Dentaria, or Tooth-wort, In fruit. + +164 +BEGINNERS' BOTANY + +fruit, as possibly in the walnut and the hickory (Fig. 255), and the cup of the acorn (Fig. 226). The chestnut and the beech bear a prickly involucre, but the nuts, + +A close-up of a chestnut nut with a prickly involucre. + +Fig. 205.--HICKORY-NUT. + +The nut is the fruit, con- +tained in a husk. + +or true fruits, are not grown fast to it, and the involucre can scarcely be called a part of the fruit. A ripened ovary is a pericarp. A pericarp to which other parts adhere has been called an accessory or reinforced fruit. (Page 169.) + +Some fruits are dehiscent, or split open at maturity and liberate the seeds; others are indehiscent, or do not open. + +A dehiscent pericarp is called a pod. + +The parts into which such a pod breaks or splits are known as valves. In inde- +hiscent fruits the seed is liberated by the decay of the envelope, or by the rupturing of the envelope by the germinating seed. +Indehiscent winged peri- +carps are known as samaras of key fruits. +Maple (Fig. +227), elm (Fig. 228), and ash (Fig. 93) are examples. + +A diagram showing the structure of a dehiscent fruit, likely a maple or elm pod. +Fig. 206.--Key of +SOUR MAPLE. + +A diagram showing the structure of a dehiscent fruit, likely a maple or elm pod. +Fig. 207.--Key of +AMERICAN Elm. + +A diagram showing the structure of a dehiscent fruit, likely a maple or elm pod. +Fig. 208.--Key of +COMMON AMERICAN Elm. + +A diagram showing the structure of a dehiscent fruit, likely a maple or elm pod. +Fig. 209.--Key of +MAPLE. + +**FRUITS** + +165 + +**Pericarp** — The simplest pericarp is a dry, one-seeded, indehiscent body. It is known as an akene. A head of akenes is shown in Fig. 229, and the structure is explained in Fig. 230. Akenes may be seen in buttercup, hapticia, anemone, smartweed, buckwheat. + +Fig. 229.—AKENES OF BUTTERCUP. + +A l-lobed pericarp which dehisces along the front edge (that is, the inner next, even the centre of the flower) is a follicle. The fruit of the larkspur (Fig. 231) is a follicle. There are usually five of these fruits (sometimes three or four) in each larkspur flower, each pistil ripening into a follicle. If these pistils were united, a single compound pistil would be formed. Columbine, pcnyon, nincbark, milkweed, also have follicles. + +Fig. 230.—AKENES OF BUTTERCUP. + +A l-lobed pericarp that dehisces on both edges is a legume. Peas and beans are typical examples (Fig. 232); in this character gives name to the pod family,—Leguminose. + +Offals the valves of the legume twist forcibly and expel the seeds, throwing them some distance. The word "pod" is sometimes restricted to legumes, but it is better to use it generically for all dehiscing pericarps. + +Fig. 231.—CAPSULE OF LARKSPUR AFTER DEHISCENCE. + +A compound pod—dehiscing pericarp of two or more carpels—is a capsule (Figs. 233, 234). + +166 +BEGINNERS' BOTANY + +236, 237). Some capsules are of one locule, but they may have been compound when young (in the ovary stage) and the partitions may have vanished. Sometimes one or more of the carpels are uniformly covered out by the exhalative growth of other carpels (Fig. 235). The seeds or parts which are crowded out are said to be abortus. + +FIG. 234.—CAY. +BUD OF MOUNT +INS GLORY. + +There are several ways in which capsules deslice or open. When they break along the partitions (or septa), the mode is known as septi- +cidal dehiscence (Fig. 230). + +In septicidaldehiscence the fruit separates into parts representing the original carpels. These carpels may still be entire, and they then dehisce individu- +ally, usually along the inner edge as if they were follicles. When the compartments split in the middle, between the partitions, the mode is localised +dehiscence (Fig. 237). In some cases the dehiscence is at the top, +when it is said to be apical (at +though general modes of dehis- +cence are hard to distinguish). +When the whole top comes off, as in purs- +lane and garden portulaca (Fig. +238), the pod is known as a pyxis. In some cases apical dehiscence is by means of a hole or clefts. + +The peculiar capsule of the mustard family, or Cruciferae, + +FIG. 235.—THREE-CARPELED FRUIT +OF HOUSE-CHERRY. Two berries are closing by abortion of the ovule. + +FIG. 236.—ST. JOHN'S BONE- +CAMPUS. + +FIG. 237.—LOCALISED DEHISCENCE +OF A FLOWER OF DAISY-LILY. + +The peculiar capsule of the mustard family, or Cruciferae, is known as a pyxis. In some cases apical dehiscence is by means of a hole or clefts. + +FRUITS +167 + +ferre, is known as a siliquæ when it is distinctly longer than broid (Fig. 224), and a silicæ when its breadth nearly + +Fig. 235.—PYXIS OF POETTI- +LACA OR ROSE-MOSS. +Fig. 236.—BERRIES OF GOOSE- +BERRY. Rosettes of corys at c. + +equals or exceeds its length. A cruciferous capsule is 2-carpeled, with a thin partition, each locule containing seeds in two rows. The two valves detach from below upwards. Cabbage, turnip, mustard, water-cress, radish, rape, shepherd's purse, sweet almond, wall-flower, honesty, are examples. + +Fig. 237.—BERRY OF THE GROUND-CHEESE +or HICK TOMATO, contained in the indusium calyx. + +The pericarp may be fleshy and indehiscent. A pulpy pericarp with several or many seeds is a berry (Figs. 239, 240, 241). To the horticulturist a berry is a small, soft, edible fruit, without + +Fig. 241.—GLANCE, example +of a berry. + +168 +BEGINNERS' BOTANY + +particular reference to its structure. The botanical and horticultural conceptions of a berry are, therefore, unlike. +In the botanical sense, gooseberries, currants, grapes, to- +matoes, potatoes, and even eggplant fruits and oranges (Fig. 241) are berries ; strawberries, raspberries, black- +berries are not. + +A fleshy pericarp containing one relatively large seed or stone is a **drupe**. Examples are plum (Fig. 242), peach, +cherry, apricot, olive. The walls of the pit in the plum, peach, and cherry are formed from the inner coats of the ovary, and the flesh from the outer coats. Drupes are also known as **stone-fruits**. + +Fruits that are formed by the sub- +sequent union of separate pistils are +**aggregate fruits**. The carpels in aggregate fruits are usually more or less fleshy. In the ras- +berry and the blackberry flower, the pistils are essentially distinct, each being a separate pistil upon they co- +here and form one body (Figs. 243, 244). + +Each of the carpels or pistils in the raspberry and the blackberry is a little drupe or **drupelet**. In the raspberry the entire fruit separates from the torns, leaving the torns on the plant. In the blackberry and + +A diagram showing a plum with a stone in the center. +FIG. 242.—PLUM: EXAMPLE OF A DRupe. + +A diagram showing a raspberry flower with several separate pistils. +FIG. 243.—AGGREGATE FRUIT: RASPBERRY. + +A diagram showing a blackberry flower with several separate pistils. +FIG. 244.—AGGREGATE FRUIT: BLACKBERRY. + +A diagram showing a drupelet in a raspberry. +FIG. 245.—DRUPELLET IN A RASPBERRY. + +A diagram showing a drupelet in a blackberry. +FIG. 246.—DRUPELLET IN A BLACKBERRY. + +Each of the carpels or pistils in the raspberry and the blackberry is a little drupe or **drupelet**. In the raspberry the entire fruit separates from the torns, leaving the torns on the plant. In the blackberry and + +**FRUITS** +169 + +the dewberry the fruit allieres to the torus, and the two are removed together when the fruit is picked. + +**Accessory Fruits.** When the pericarp and some other part grow together, the fruit is said to be accessory or reinforced. An example is the strawberry (Fig. 245). The edible part is a greatly enlarged torus, and the pericarps are akaces embedded in it. These akaces are commonly called seeds. + +Various kinds of reinforced fruits have received special names. One of these is the bit, characteristic of roses. In this case, the torus is deep and hollow, like an urn, and the separate akaces are borne inside it. The mouth of the receptacle may close, and the walls sometimes become fleshy; the fruit may then be mistaken for a berry. The fruit of the pear, apple, and quince is known as a + +A diagram showing a section of a fruit with a hollow torus and embedded akaces. +**Fig. 245.—SECTION OF A PEAR.** + +**pome.** In this case the five united carpels are completely buried in the hollow torus, and the torus makes most of the edible part of the ripe fruit, while the plasts are represented by the core (Fig. 245). Observe the scars on the top of the torus (spots of the fruit) in Fig. 245. Note the outlines of the embedded pericarp in Fig. 247. + +A diagram showing a cross-section of a pome fruit with a hollow torus and embedded akaces. +**Fig. 247.—CROSS-SECTION OF AN APPLE.** + +170 +BEGINNERS' BOTANY + +Gymnospermous Fruits.—In pine, syruses, and their kin, +there is no fruit in the sense in which the word is used +in the preceding pages, because there is no ovary. The +ovules are naked or uncovered, in the axis of the scales of +the young cone, and they have neither style nor stigma. +The pollen falls directly on the mouth of the ovule. The +ovule ripens into a seed, which is usually winged. Because +the ovule is not borne in a sac or ovary, these plants are +called **gymnosperms** (Greek for "naked seeds"). All the +true cone-bearing plants are of this class; also certain +other plants, as red cedar, juniper, yew. The plants are +monocuous or sometimes dioecious. The stamine flowers +are mere naked stamens borne beneath scales, in small +yellow catkins which fall off. The pistillate flowers are +naked and borne on scale-like scales on cones only. (Fig. +29.) + +Gymnospermous plants may have several cotyledons. + +**Succulentus—168.** Among the following fruits, or my five fruits +chosen by the teacher, and answer the questions for each: Apple, +peach, bean, tomato, pumpkin. What is its form? Locate the +seed within it. Is it covered with a shell? How many seeds? +Are there any remains of the blossom on the blossom end? De- +scribe texture and colour of surface. Divide the fruit into the seed +vein and the outer covering. Is there a seed in this fruit? Is it +with or without the seed vessel? In the seed vessel single or sub-divided? What is the number of seeds? Are the seeds few, +many, or numerous? Where do they grow? What part of the tree is +centre? Are they arranged in one order? What kind of wall has +the seed cover? What is the difference between a peach stone and a cherry stone? What is the difference between a fig and a fig for- +tuity. Note the points suggested above. Determine what the +man or edible parts represent, whether cotyledon or ear. Figure 29 is to help you in your work. Can you tell how many ears you know, +tell where they come from, and refer them to their proper groups. +171. What kinds of fruit can you name that have no seeds? +What are they called? Of which fruits are the seeds only, +and not the pericarp, eaten? 172. An ear of corn is always available at school time. How many rows does it have? +How are the grains arranged on the cob? How many rows do +you count on each of several ears? Are all the rows on an ear + +**FEUITS** + +171 + +equally close together? Do you find an ear with an odd number of rows? How do the parts of the heart overlap? Does the hook serve as protection from rain? Can birds pick out the grime? How do insects encase enter the ear? How and when does recrystalline hay emerge on corn? 173. A grain of grass is a seed? Does the ear have a stalk? Does the ear surface show any projections or depressions? Is the seed-outer thin or thick? Transparent or opaque? Locate the hilum. Where is the silk seen? What is the shape of the grain from the two perspectives view this shows best. Where is the base? Does the grain have endosperm? What is dent corn? Flint corn? How many kinds of corn do you know? For what are they used? + +Fig. n8.--Pecan fruit. + +NOTE TO TEACHER.--There are few more interesting subjects to beguile pupils than fruits--the paks of many kinds, forms, and colours, the berries, and nuts. This interest may well be utilized to make the teaching alive. All common edible fruits of garden and vegetable gardens should be harvested into this dissection. The specimens may be brought home and carefully made for the school museum. Fully mature fruits are best for study, particularly if it is desired to see dehiscence. For comparative purposes, a particularly mature fruit should be had at each season time. If the specimen is not ripe enough to dehiscene, they may be placed in the sun to dry. In the school it will be well to have a collection of fruits for study. The specimens may be kept in a glass case, or in a box lined with paper, with a paste, interior of fruit with arrangement and attachment of contraints. + +Note to teacher.--There are few more interesting subjects to beguile pupils than fruits--the paks of many kinds, forms, and colours, the berries, and nuts. This interest may well be utilized to make the teaching alive. All common edible fruits of garden and vegetable gardens should be harvested into this dissection. The specimens may be brought home and carefully made for the school museum. Fully mature fruits are best for study, particularly if it is desired to see dehiscence. For comparative purposes, a particularly mature fruit should be had at each season time. If the specimen is not ripe enough to dehiscene, they may be placed in the sun to dry. In the school it will be well to have a collection of fruits for study. The specimens may be kept in a glass case, or in a box lined with paper, with a paste, interior of fruit with arrangement and attachment of contraints. + +CHAPTER XXII + +DISPERAL OF SEEDS + +It is to the plant's advantage to have its seeds distributed as widely as possible. It has a better chance of surviving in the struggle for existence. It gets away from competition. Many seeds and fruits are of such character as to increase their chances of wide dispersal. The commonest means of dissemination may be classed under four heads : explosive fruits ; transportation by wind ; transportation by birds ; burs. + +A butterfly with a flower in its mouth. +Fig. 293.--EXPLOSIVE FRUITS OF OXALIS. +An exploding pod is shown in Fig. 294. The structure shown at A. The structure of this pod is seen at B. + +Fig. 292.--EXPLANATION OF THE BALAM POD. +Explosive Fruits.--Some pods open with explosive force and discharge the seeds. Even beans and everlasting peas do this. More marked examples are the locust, witch hazel, garden balsam (Fig. 249), wild jewel-weed or impatiens (touch-me-not), violet, crane's-bill or wild geranium, bull nettle, morning glory, and the oxalis (Fig. 250). The + +172 + +DISPERAL OF SEEDS + +173 + +oxalis is common in several species in the wild and in cultivation. One of them is known as wood sorrel. Figure 250 shows the common yellow oxalis. The pod opens locallyidically. The elastic tissue suddenly contracts when dehiscence takes place, and the seeds are thrown violently. The squirting cucumber is easily grown in a garden (pro- cure seeds of seedsmen), and the Fruits discharge the seeds with great force, throwing them many feet. + +Wind Travelers. — Wind-transported seeds are of two general kinds: those that are provided with wings, as the flat seeds of catnip (Fig. 251) and cone-bearing trees and the samaras of ash, elm, tulip-tree, alnus, and maple; and those which have feather bristles or para- chutes to enable them to float in the air. Of the latter kind are the fruits of many composites, in which the pappus is copious and soft. Dandelion and thistle are examples. The silk of the milkweed and probably the hairs on the cotton seed have a similar office, and also the wool of the cat-tail. Recall the cottony seeds of +Figure 251 - Wind-transported seeds. +the willow and the poplar. + +Dispersal by Birds. — Seeds of berries and of other small fleshy fruits are carried for and wide by birds. The seeds in figs digested by the birds are not injured. Note how the cherries, raspberries, blackberries, June-berrys, and others spring up in the fence rows, where the birds rest. Some berries and drupes persist far into winter, when they supply food to cedar birds, robins, and the winter birds. Red cedar is distributed by birds. Many of these pulpy + +174 + +fruits are agreeable as human food, and some of them have been greatly enlarged or "improved" by the arts of the cultivator. The seeds are usually indigestible. + +**Burs.** — Many seeds and fruits bear spines, hooks, and hairs, which adhere to the coats of animals and to clothing. The burdock has an involucre with hooked scales, containing the fruits inside. The clover is also an involucre. Both are composite plants, allied to thistles, but the whole head rather than the separate fruits are transported. In some composite fruits the pappus takes the form of hooks and spines, as in the "Spanish bayonets" and "pitchforks." Fruits of various kinds are known as "stick tights," as of the agrimony and hound's-tongue. Those who walk in the woods in late summer and fall are aware that plants have means of disseminating themselves (Fig. 53). If it is impossible to identify the burs which one finds on clothing, the seeds may be planted and specimens of the plant may then be grown. + +**Suggestions.** — 174. What advantage is it to the plant to have its seeds widely dispersed? 175. What are the leading ways in which this is accomplished? 176. What are the most offensive fruits. 177. Describe wind travelers. 178. What seeds are carried by birds? 179. Describe some bur with which you are familiar. 180. Are adhesive fruits mainly dependent upon animals? 181. How do many plants act as a rule? 182. Are the cotton flaves on the seed or on the fruit? 183. Name the ways in which the common weeds of your region are disseminated. 184. This lesson will suggest other ways in which + +A close-up of a burr plant. +**FIG. 25a.—STEALING A RIDE.** + +DISPERAL OF SEEDS - 175 + +seeds are transported. Nuts are buried by squirrels for food ; but if they are not eaten, they may grow. The seeds of many plants are blown on the small streams and rivers, where they may float through the winter, may serve to disseminate the plant. Seeds are carried by water down the streams and along shores. About 10000 mills of water are needed to carry one seed from the river to the ocean. Sometimes the entire plant is rolled for miles before the winds. Such plants are "tumbleweeds." Examples are Russian thistle, bur-grass, and the common sunflower. Another tumbleweed plant (Cycloboia platyphyllum), and white amaranth (Amarantus albus). Almost seaports strange plants are often found, having been blown in from distant lands by the winds. These are called ballast plants. These plants are usually known as "ballast plants." Most of them do not persist long. 165. Plants are able to spread themselves by means of the great numbers of seeds that they produce. How many seeds may a given elm tree or apple tree or raspberry bush produce? + + +The fruit of the cat-tail aee loosened by wind and weather. + + +Fig. 93.-THE FRUIT OF THE CAT-TAIL AEE LOOSENED BY WIND AND WEATHER. + +CHAPTER XXIII + +PHENOGAMS AND CRYPTOGAMS + +The plants thus far studied produce flowers; and the flowers produce seeds by means of which the plant is propagated. There are other plants, however, that produce no seeds, and these plants (including bacte- +ria) are probably more numer- +ous than the seed-bearing plants. +These plants propagate by means of spores, which are generative cells, +nearly simple, containing no em- +bryo. These spores are very small, +and sometimes are not visible to the naked eye. + +Prominent among the spore- +propagated plants are ferns. The +common Christmas fern (so called because it remains green during winter) is shown in Fig. 254. The plant has no trunk. The leaves spring directly from the ground. The leaves of ferns are called fronds. They vary in shape, as other leaves do. Some of the fronds in Fig. 254 are seen to be narrower at the base. If these are examined more closely (Fig. 255), + +Fig. 253.—CHRISTMAS FERN. +—Dryopteris aconitochlora; +known also as Aquidium. + +Fig. 254.—FRONDS OF CHRISTMAS FERN. +See also one series with its im- +pressions at d. + +PHENOGAMS AND CRYPTOGAMS +177 + +it will be seen that the leaflets are contracted and are densely covered beneath with brown bodies. These bodies are collections of *sporangia* or *spore-cases*. + +Fig. 253.—Sori and Sporo- +ganula of Polytope.* +A chain of cells lies along the upper side of the sorus, +which springs back clas- +sically on drying, thus dis- +summing the spores. + +**Fig. 254.—CHIRON POLYTOPE FERN.** +Polyptogium virgin. + +The *sporangia* are collected into little groups, known as *sori* (singular, *sorus*) or *fruit-dots*. Each *soru* is covered with a thin scale or shield, known as an *indusium*. This indusium sepa- +rates from the frond at its edge, and +the *sporangia* are exposed. Not all +forms have indusia. The polypode +(Figs. 256, 257) does not; the *sori* +are naked. In the brake (Fig. 248) +and maidenhair (Fig. 250) the +edge of the frond turns over +and forms an indusium. The +nephrolepis or sword fern of +greenhouses is allied to the +polypode. The *sori* are in a +single row on either side the +midrib (Fig. 250). The indu- +sium is circular or kidney- +shaped and open at one edge + +**Fig. 255.—FRUITING PYGMELES OF MAIDENHAIR FERN.** + +Fig. 256.—The Brake +THUCCHEMENAEATH +with fruiting *Eggs of the Leaf.* +Fig. 257.—The Maidenhair FERN. + +178 +BEGINNERS' BOTANY + +Fig. 260.--Flax of France, or +Sword Fern. To the pupil: Is +this illustration right side up? + +or finally all around. The +Boston fern, Washington fern, +Picorn fern, and others, are +horticultural forms of the +common sword fern. In some +ferns (Fig. 261) an entire +frond becomes contracted to +cover the sporangia. + +The sporangium or spore-case of a fern is a more or less +globular body and usually with a stalk (Fig. 257). It con- +tains the spores. When ripe it +burst and the spores are set free. +In a moist, warm place the spores +germinate. (Fig. 262.) This +is the prothallus. Sometimes the +prothallus is an inch or more across, +but often it is less than ten cen- +tims in size. Although easily +seen, it is commonly unknown ex- +cept to botanists. Prothallus may +often be found in greenhouses where ferns are grown. +Look on the moist stone or +brick walls, or on the firm soil +of undisturbed pots and beds; +or spores may be sown in a +damp, warm place. + +On the under side of the +prothallus two kinds of organs +are borne. These are the +archegonium (containing egg- +cells) and the antheridium (con- + +Fig. 261.--PROTHALLUS OF A FERN. Eulophia. +Archegonium at a ; antheridium at b. + +Fig. 260.--Flax of France, or Sword Fern. +Fig. 261.--Prothallus of a fern. + +PHENOGAMS AND CRYPTOGAMS + +179 + +taining sperm-cells). These organs are minute specialized parts of the prothallus. Their positions on a particular prothallus are shown at $a$ and $b$ in Fig. 262, but in some ferns they are on separate prothalli (plant dichotomies). The sperm-cells escape from the antheridium and in the water that collects on the prothallus are carried to the archegonium, where fertilization of the egg takes place. From the fertilized egg-cell a plant grows, becoming a "fern". In most cases the prothallus soon dies. The prothallus is the gametophyte (from Greek, signifying the fertilized plant). + +The fern plant, arising from the fertilized egg in the archegonium, becomes a perennial plant, each year producing spores from its fronds (called the sporophyte); but these spores—which are merely detached special kinds of cells—produce the prothallial phase of the fern plant, from which new individuals arise. A fern is fertilized but once in its lifetime. The "fern" bears the spore, the spore gives rise to the prothallus, and the egg-cell of the prothallus (when fertilized) gives rise to the fern. + +A similar alternation of generations runs through all the vegetable kingdom, although there are some groups of plants in which it is very obscure or apparently wanting. It is very marked in ferns and mosses. In algae (including the seaweeds) the gametophyte is the "plant", as the non-botanist knows it, and the sporophyte is inconspicuous. There is a general tendency, in the evolution of the vegetable kingdom, for the gametophyte to lose its relative importance and for the sporophyte to become larger and more highly developed. In the seed-bearing plants the sporophyte generation is the only one seen by the non-botanist. The gametophyte stage is of short duration and the parts are small; it is confined to the time of fertilization. + +180 + +**BEGINNERS' BOTANY** + +The sporophyte of seed plants, or the "plant" as we know it, produces two kinds of spores—one kind becoming pollen grains and the other kind embryo-sacs. The pollen-spores are borne in sporangia, which are united into what are called anthers. The embryo-sac, which contains the egg-cell, is borne in a sporangium known as an *ovule*. A gametophytic stage is present in both pollen and embryo sac: fertilization takes place, and a sporophytic species. Soon this sporophyte becomes dormant, and it then known as an embryo. The embryo is packed away within tight-fitting coats, and the entire body is the seed. When the conditions are right the seed grows, and the sporophyte grows into herb, bush, or tree. The utility of the alternation of generations is not understood. + +The spores of ferns are borne on leaves; the spores of seed-bearing plants are also borne amongst a mass of specially developed conspicuous leaves known as flowers; therefore these plants have been known as the flowering plants. Some of the leaves are developed as envelopes (calyx, corolla), and others as spore-bearing parts, or **sporophytes** (stamens, pistils). But the spores of the lower plants—of ferns mostly—are not borne in specifically developed pistils, so that the line of distinction between flowering plants and flowerless plants is not so definite as was once supposed. The one definite distinction between these two classes of plants is the fact that one class produces seeds and the other does not. The seed-plants are now often called spermatophytes, but there is no single coordinate term to set off those which do not bear seeds. It is quite as well, for popular purposes, to use the terms **phagomorphs** for the seed-bearing plants and **cryptogams** for the others. These terms have been objected to in recent years because their etymology does not express literal facts + +PHENOTYPES AND CRYPTOTYPES + +(Phenogram signifying "showy flowers," and cryptogram "(hidden flowers"), but the terms represent distinct ideas in classification. The cryptogams include three great series of plants—the Thallophytes or alge, lichens, and fungi; the Bryophytes or mosslike plants; the Pteridophytes or fernlike plants. + +Sciosciarex. — 168. The form of a fern leaf. The primary compound frond is called pinnate or not. In ferns the word "pinnate" is used in essentials only when the leaf is in the once-component leaves of other plants. The secondary branches (fronds) are simple, or thricose, or more, compound fronds, the last complete parts or leaflets are unifoliate (Fig. 253). The midrib of a compound frond (Fig. 254) will aid in making the subject clear. If the frond were not divided to the midrib, it would be called a simple frond, which represents a compound frond. The general outline of the frond, as shown in Fig. 255, is usually ovate. The stipe is very short. The midrib of a compound frond is known as the rachis. A leafless compound frond, this main rachis is called the primary rachis. Segments (leaflets) of a compound frond are seen at the tip, and down to e on one side and up to w on the other. The segments are pinnate (Fig. 178, a). The pinnule is entire; e is crenate-dentate; i is simate or wavy, with an auricle at the base; j and f are compound. The pinnule has twelve entire pin- +nules. The pinnule is entire (Fig. 178, b). The pinnule has nine compound pinnules, each bearing several entire ultimate pinnules. The pinnule — 187. Lay a mature fruiting frond of any fern on white paper, top side up, and allow it to remain in dry air for two days. Then turn over the paper and place it under a lighted lamp for ten minutes. +188. Lay the full-grown (but not dry) cap of a mushroom or toadstool (bottom down) on a sheet of cellophane paper, under a venti- +lated box in a warm, dry place. A tiny blister raise the cap. + +Diagram to explain the terminology of the fern. +181 + +CHAPTER XXIV + +STUDIES IN CRYPTOGAMS + +The pupil who has acquired skill in the use of the com- +pound microscope may desire to make more extended ex- +cursions into the cryptogamous orders. The following +plants have been chosen as examples in various groups. +Ferns are sufficiently discussed in the preceding chapter. + +BACTERIA + +If an infusion of ordinary hay is made in water and allowed to stand, it becomes turbid or cloudy after a few days, and a drop under the cover-glass shows a profuse growth of long, thread-like cells swimming in the water, perhaps by means of numerous hair- +like appendages, that project through the cell wall from the pro- +toplast within. At the surface of the dish containing the infusion, +the cells are seen to be surrounded by a film of water. Each +of these cells or organisms is a bacterium (plural, bacteria). +(Fig. 135.) + +Bacteria are very minute organisms,—the smallest known— +consisting either of separate oblong or spherical cells, or of +chains, plates, or groups of such cells, depending on the kind. +They vary greatly in size, but all contain a nucleus. Most of +higher plants, contains nitrogen. The presence of a nucleus has not been definitely demonstrated. Multiplication is by the fission +of the cell wall, which is usually thin and easily torn by slight +cold, or exhaustion of the nutrient medium, the protoplasm of +the ordinary cells may become invested with a thick wall, thus form- +ing an endospore, which is resistant to extremes of environ- +ment. No sexual reproduction is known. + +Bacteria are very widely distributed as parasites and super- +viruses in almost all living things. They are often found associated +by bacteria accompanied in animal tissue by the liberation +of foul-smelling gases. Certain species grow in the reservoirs +and pipes of water supplies, rendering the water brackish and often +unfit for drinking. In this way they contribute to the de- +composing of organic compounds, usually accompanied by the + +182 + +STUDIES IN CRYPTOGAMS + +183 + +formation of gas) are due to these organisms. Other bacteria oxidize alcohol to acetic acid, and produce fatty acids in milk and other substances. They also produce gases, such as hydrogen, carbonic acid, the intestinal, and on the surface of the skins of animals. Some secrete gelatinous sheaths around themselves; others secrete mucus or slime in globules. + +Were it not for bacteria, man could not live on the earth, for not only are they agents in the process of decay, but they are concerned with the production of food for all living things. + +We have learned in chapter VIII how bacteria are related to nitro- +gen-gathering. + +Bacteria of economic importance not alone because of their effect on materials used by man, but also because of the disease- +producing power of certain species. Pus is caused by a spherical bacillus, known as typhoid fever, by a non-spherical bacillus by short oblong chains, tubercle-bacillus consumption" by more shor- +toblong chains, and typhoid fever, cholera, and other diseases by other forms. Many diseases of animals and plants are caused by bacteria. Disease-producing bacteria are said to be pathogenic. + +The ability to grow in other infinitesimal substances than the natu- +ral one is a great advantage to bacteria in their struggle for life. The use of suitable culture media and proper precu- +sors, pure cultures of a particular disease-producing bacterium may be obtained with which further experiments may be con- +ducted. + +Milk provides an excellent collecting place for bacteria coming +from the mouth and nose of people who drink it. Disease +germs are sometimes carried in milk. If a drop of milk is +spread on a culture medium (as agar), and provided with proper +organisms, colonies will appear within 24 hours. A single colony +visible to the naked eye. In this way, the number of bacteria +originally contained in the milk may be counted. + +Bacteria are disseminated in water, as the germ of typhoid fever +and cholera; in air; on leaves; on the bodies of flies, feet of birds, and otherwise. +Bacteria are thought by many to have descended from algae by +the loss of chlorophyll and pigments. This suggestion due to the more +specialized acquired saprophytic and parasitic habit. + +A.I.C.E. + +The alga comprise most of the green floating " scum " which +covers the surface of ponds and other quiet waters. The masses +of plants are often called " frog spittle." Others are attached to +stones, pieces of wood, and other objects submerged in streams + +184 + +**BEGINNERS' BOTANY** + +and lakes, and many are found on moist ground and on dripping rocks. Aside from these, all the plants commonly known as seaweeds belong to this category; these latter are inharmonious with the plants of fresh water, which are generally more beautiful. The simplest forms of algae consist of a single spherical cell, which is surrounded by a gelatinous film. The body of the plants formed in fresh water are filamentous, i.e. the plant body consists of long threads, either simple or branched. Such a plant body is called a filamentous plant. The simplest body of all plants that are not differentiated into stem and leaves. Such plants are known as thallophytes (p. 181). All algal contain chlorophyll, but only the green algae absorb light from the air. + +**Note.** — On wet rocks and damp soil dark, transparent irregular or spherical gelatinous masses about the size of a pea are often found. These consist of a colony of contorted filamentsous algae growing together in one mass. The cells composing the filament are necklace-like. Each cell is homogeneous, without apparent nucleus, and blue-green in colour except one cell which is large and contains a nucleus. This cell belongs to the group of blue-green algae. The jelly probably serves to maintain a more even measure and to provide mechanical protection, but no other special function appears. + +**Oscillatoria.** — The blue-green coatings found on rocks and stones frequently show under the microscope the presence of filamentous algae composed of many short + +Fig. 26a.—Filament of Oscillatoria, showing one dead cell where the strand will break. +homogeneous cells (Fig. 26a). If watched closely, some filaments will be seen to wave back and forth at regular intervals, showing the movement characteristic of this plant. Multiplication is by the breaking up of the thread. Thus, one free space becomes two. + +**Spirogyra.** — One of the most common forms of the green algae is strogynia (Fig. 26b). This + +Fig. 26b.—SYLLOGYRA, +shows the chlorella-like cells. There is a nucleus at each end of parts of cells, shown in this fig- +ure. + +Fig. 26c.—SYLLOGYRA, +showing the chlorella-like cells. +There is a nucleus at each end of parts of cells, shown in this fig- +ure. + +STUDIES IN CRYPTOGAMS + +plant often forms the greater part of the floating green mass (or "frog spittle") on ponds. The thread-like character can be seen with the naked eye or with a hand lens, but to see the individual threads clearly, magnifying two hundred diameters or more must be used. The thread is divided into long cells by transverse walls, which may be one or two, or species, are either straight or curiously folded (Fig. 260). The chlorophyll is arranged in long leaf-shaped plates, which are attached to the walls. + +From the character of these bands the plant takes its name. Each cell is provided with a nucleus, and a protoplast, suspended near the centre of the cell (Fig. 265) by delicate strands of protoplasm radiating over towards the walls. These strands form points in the chlorophyll band. The remainder of the protoplasm forms a thin lining layering the wall. The outermost layer is called the cell-sap. The protoplasm and nucleus cannot be easily seen, but if the plant is stained with a dilute alcoholic solution of caine they become clearer. + +Spirogyra is propagated vegetatively by the breaking off parts of the threads, which con- tinue to grow outwards until they reach a point which may remain dormant for a time, are formed by a process known as conjugation. Two threads lying side by side are joined together at their ends from all the cells of a line series (Fig. 266). The projections or processes from opposite cells connect each other by means of a tube com- pecting a connecting tube between the cells. The protoplasm, nucleus, and chlorophyll band of one cell passes through this tube, and unites with the contents of the other cell. The en- tire mass then becomes surrounded by a thick cellulose wall, thus completing the restag- ing of Spirogyra (Fig. 267). + +Zygogonium is also closely related to spi- rogyra and grows in similar places. Its life history is practically the same, but it differs from Spirogyra in having two star-shaped endocellular bodies (Fig. 265) in each cell, in- ternal of a chlorophyll-bearing spiral band. + +185 + +A diagram showing the structure of Spirogyra. +Illustration showing Spirogyra's structure. + +260 +Illustration showing Spirogyra's structure. + +265 +Illustration showing Spirogyra's structure. + +267 +Illustration showing Spirogyra's structure. + +266 +Illustration showing Spirogyra's structure. + +261 +Illustration showing Spirogyra's structure. + +263 +Illustration showing Spirogyra's structure. + +264 +Illustration showing Spirogyra's structure. + +262 +Illustration showing Spirogyra's structure. + +268 +Illustration showing Spirogyra's structure. + +269 +Illustration showing Spirogyra's structure. + +270 +Illustration showing Spirogyra's structure. + +271 +Illustration showing Spirogyra's structure. + +272 +Illustration showing Spirogyra's structure. + +273 +Illustration showing Spirogyra's structure. + +274 +Illustration showing Spirogyra's structure. + +275 +Illustration showing Spirogyra's structure. + +276 +Illustration showing Spirogyra's structure. + +277 +Illustration showing Spirogyra's structure. + +278 +Illustration showing Spirogyra's structure. + +279 +Illustration showing Spirogyra's structure. + +280 +Illustration showing Spirogyra's structure. + +281 +Illustration showing Spirogyra's structure. + +282 +Illustration showing Spirogyra's structure. + +283 +Illustration showing Spirogyra's structure. + +284 +Illustration showing Spirogyra's structure. + +285 +Illustration showing Spirogyra's structure. + +286 +Illustration showing Spirogyra's structure. + +287 +Illustration showing Spirogyra's structure. + +288 +Illustration showing Spirogyra's structure. + +289 +Illustration showing Spirogyra's structure. + +290 +Illustration showing Spirogyra's structure. + +291 +Illustration showing Spirogyra's structure. + +292 +Illustration showing Spirogyra's structure. + +293 +Illustration showing Spirogyra's structure. + +294 +Illustration showing Spirogyra's structure. + +295 +Illustration showing Spirogyra's structure. + +296 +Illustration showing Spirogyra's structure. + +297 +Illustration showing Spirogyra's structure. + +298 +Illustration showing Spirogyra's structure. + +299 +Illustration showing Spirogyra's structure. + +300300 +
An illustration of Zygogonium, a type of aquatic plant that resemblesSpirogyra in its appearance and growth habits. It has a central rod-like body surrounded by a ring of smaller cells, all connected by fine threads. The central rod contains chloroplasts and appears to be photosynthetic. The surrounding cells contain nuclei and appear to be non-photosynthetic. The entire organism is enclosed in a protective sheath that appears to be made of cellulose. This sheath is likely to be used for protection against predators and environmental stressors. The organism appears to be able to move by means of flagella that extend from the central rod. These flagella are likely to be used for locomotion and may also be involved in reproduction. The organism appears to be able to reproduce sexually by means of gametes that are produced within the central rod. These gametes are likely to be used for fertilization and may also be involved in reproduction. The organism appears to be able to reproduce asexually by means of binary fission, where one organism divides into two identical organisms. This process is likely to be used for rapid population growth and may also be involved in reproduction. The organism appears to be able to survive in a wide range of environments, including freshwater ponds, lakes, and rivers. This ability is likely to be due to its ability to produce a protective sheath that can withstand harsh conditions. The organism appears to be able to adapt to changing environmental conditions by means of genetic variation and natural selection. This ability is likely to be due to its ability to produce new genetic variations through mutation and recombination, and its ability to respond to environmental changes through adaptation and evolution. The organism appears to be able to interact with other organisms in its environment through various mechanisms, including predation, competition, and symbiosis. This interaction is likely to be important for maintaining ecological balance and stability. +
Zygogonium is an aquatic plant that resemblesSpirogyra in its appearance and growth habits. It has a central rod-like body surrounded by a ring of smaller cells, all connected by fine threads. The central rod contains chloroplasts and appears to be photosynthetic. The surrounding cells contain nuclei and appear to be non-photosynthetic. The entire organism is enclosed in a protective sheath that appears to be made of cellulose. This sheath is likely to be used for protection against predators and environmental stressors. The organism appears to be able to move by means of flagella that extend from the central rod. These flagella are likely to be used for locomotion and may also be involved in reproduction. The organism appears to be able to reproduce sexually by means of gametes that are produced within the central rod. These gametes are likely to be used for fertilization and may also be involved in reproduction. The organism appears to be able to reproduce asexually by means of binary fission, where one organism divides into two identical organisms. This process is likely to be used for rapid population growth and may also be involved in reproduction. The organism appears to be able to survive in a wide range of environments, including freshwater ponds, lakes, and rivers. This ability is likely to be due to its ability to produce a protective sheath that can withstand harsh conditions. The organism appears to be able to adapt to changing environmental conditions by means of genetic variation and natural selection. This ability is likely to be due to its ability to produce new genetic variations through mutation and recombination, and its ability to respond to environmental changes through adaptation and evolution. The organism appears to be able to interact with other organisms in its environment through various mechanisms, including predation, competition, and symbiosis. This interaction is likely to be important for maintaining ecological balance and stability. +

Spirogyra:  Spirogyraceae,  PHYCOPHYTA,  Fusarium,  Cyanobacteria,  ZYGOGONIUM,  Eriodictyon,  Glycine,  Inhospitable,  snowy,  wintergreen,  vining,  tubular,  ciliate,  bent,  fleshy,  pale,  dull,  brownish,  brownish-green,  brownish-red,  brownish-yellow,  brownish-orange,  brownish-purple,  brownish-blue,  brownish-black,  brownish-grey,  brownish-white,  brownish-bluish-green,  brownish-bluish-grey,  brownish-bluish-black,  brownish-bluish-grey-black,  brownish-bluish-grey-white,  brownish-bluish-grey-black-white,  brownish-bluish-grey-black-white-blue-green-

Zygogonium alpinum:  A small aquatic plant resemblingSpirogyra in appearance and growth habits.<br>It has a central rod-like body surrounded by a ring of smaller cells, all connected by fine threads.<br>The central rod contains chloroplasts and appears to be photosynthetic.<br>The surrounding cells contain nuclei and appear to be non-photosynthetic.<br>The entire organism is enclosed in a protective sheath that appears to be made of cellulose.<br>This sheath is likely to be used for protection against predators and environmental stressors.<br>The organism appears to be able to move by means of flagella that extend from the central rod.<br>These flagella are likely to be used for locomotion and may also be involved in reproduction.<br>The organism appears to be able to reproduce sexually by means of gametes that are produced within the central rod.<br>These gametes are likely to be used for fertilization and may also be involved in reproduction.<br>The organism appears to be able to reproduce asexually by means of binary fission, where one organism divides into two identical organisms.<br>This process is likely to be used for rapid population growth and may also be involved in reproduction.<br>The organism appears to be able to survive in a wide range of environments, including freshwater ponds, lakes, and rivers.<br>This ability is likely to be due to its ability to produce a protective sheath that can withstand harsh conditions.<br>The organism appears to be able to adapt to changing environmental conditions by means of genetic variation and natural selection.<br>This ability is likely to be due to its ability to produce new genetic variations through mutation and recombination, and its ability</p>

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An illustration of Zygogonium.
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The organism appears</div>to have been adapted for survival under</div>extreme conditions such as</div>cold temperatures,</div>poor nutrients,</div>and</div>salt water.</div>It has developed</div>a</div>protective</div>sheath</div>that</div>can</div>withstand</div>these</div>conditions.</div>Additionally,</div>it</div>has</div>a</div>high</div>rate</div>of</div>reproduction,</div>which</div>maintains</div>a stable population size even under</div>tough</div>conditions.</div> + +

An illustration of Zygogonia.
+

The organism appears</div>to have been adapted for survival under</div>extreme conditions such as</div>cold temperatures,</div>poor nutrients,</div>and</div>salt water.</div>It has developed</div>a</div>protective</div>sheath</div>that</div>can</div>withstand</div>these</div>conditions.</div>Additionally,</div>it</div>has</div>a</div>high</div>rate</div>of</div>reproduction,</div>which</div>maintains</div>a stable population size even under</div>tough</div>conditions.</div> + +

...more text...186 +**BEGINNERS' BOTANY** + +*Vaucheria* is another alga common in shallow water and on damp soil. The thallus is unbranched, but the threads are not divided by cross walls as in *spongia*. The plants are attached by means of a short stalk to the substratum, and the roots hairs of the higher plants; these are rhizoids. The chlorophyll is in the form of grains scattered through the thallus. + +*Vaucheria* is propagated by means of spores or swarm-spores. These are formed singly in a short enlarged lateral branch known as the *sporangium*. When this has matured, it produces a large number of spores in a single large *sporangium*, which swells out by means of numerous l sesses or cells on its surface. The swarm spores are so large that they can be seen with the naked eye. After swimming about for some time they come to rest on the bottom and produce a new plant. + +The formation of resting-spores of *vaucheria* is accomplished by means of special organs, *orgaena* (fig. 268) and *antheridia* (fig. 269). These organs are produced at the apex of the thallus, and are sheded separately from the thallus. The antheridia are nearly cylindrical, and contain a large number of egg-cells. + +Fig. 268. -- Thread of Vaucheria with *Oogonia* and *Antheroia* + +The upper part of an antheridium is cut off by a crescent-shaped membrane. + +Numerousiliated sperm-cells are formed. These escape by the ruptured apex of the antheridium. The oogonia are more enlarged than the sperm-cells, and have a little to one side of the apex. They are separated from the thallus thread by a cross wall, and contain a single large green cell, which is fertilized by a sperm-cell passing through the opening the sperm-cells enter. Fertilization is thus accomplished. After fertilization the egg-cell becomes invested with a thick wall and is thus converted into a resting-spore, the *oogon.* + +**Ficus.* -- These are rather larger specialized algae belonging to the group known as brown seaweeds and found attached by a link to the rocks of the seashore just below high tide (fig. 260). They are firm and strong to resist wave action and are so attached as to bend under pressure without breaking away. In shape the plants are long, branched, and multicellular, with either flat or tenrib branches. They are olive-brown. Propagation is by the breaking off of the branches. No zoospores are produced, as in many other seaweeds; and reproduction is wholly sexual. + +STUDIES IN CRYPTOGRAMS + +The authorithus, bearing *gym*-cells, and the *spongia*, each bearing eight *egg*-cells, are sunk in pits or *com*-*pacta*. These pits are aggregated in the swollen lighter colored tips of some of the branches. The eggs are fertilized by the spermatozoa which escape from the pits and fertilization takes place in the water. The matured eggs, or spores, reproduce the fucus plant directly. + +**Fig. 369. - Fucus. Frosting branchlet of a.f. On the stem are two air-bubbles.** + +**Fig. 370. - Nitella.** + +Nitella.--This is a large branched and specialized fresh-water alg, found in tufts attached to the bottom of shallow ponds (Fig. 370). The long slender branches are long narrow tubes consisting of a single cylindrical cell, which is one of the largest cells known in vegetable tissue. Under the microscope the walls of this cell are found to be composed of a number of layers, alternately within which layer the protoplasm, in favourable circumstances, will be found in motion, moving up one side and down the other (in rotation) until it then streak up the side of the cell and its relation to the moving current. + +**Fungi** + +Some forms of fungi are familiar to every one. Mushrooms and toadstools, with their various forms and colours are common in fields, woods, and pastures. In every household the common moulds are familiar intruders, appearing on old bread, vegetables, and even on our own hands. They are often seen as a white like layer dusted over with brown, yellow, or black powder. The strange occurrence of these plants long mystified people who + +188 + +BEGINNINGS' BOTANY + +...it were productions of the dead matter upon which they grow, but now we know that a moss, as any other plant, cannot originate spontaneously; it must start from something that is already existing. A spore may be produced by a sporiferous process (growing out from the ordinary plant tissue), or E may be the result of a fertilization process. + +Favorable conditions for the growth of fungi--Place a piece of bread under a moist bell jar and, on an uncovered place near by. Sow meal on each. Note the result from day to day. Maintain a thermometer. The moisture will evaporate quickly. (b) Stir into or mercerize chlorotic solution, sawdust, cow-dung, etc., with water. Place in a damp atmosphere and observe. The spores will germinate. Expose pieces of different kinds of food in a damp atmosphere and observe their germination. The spores are asporophytes or parasitic, and must be provided with organic matter on which to live. The spores are most abundant in moist places and wet seasons. + +Mycelium of Mucor muscorum. +**Mycelium.--One of these mounds (Mucor muscorum, showing bulb) is very common in all decayed wood and vegetable refuse as shown in Fig. 271, somewhat magnified. When fruiting, this mycelium appears as a dense mass of white threads growing from the stalks or fructifications from the fruit or the vegetables on which it is growing. +The life of this mycium begins with a minute roundelled spore (see Fig. 272). This spore is surrounded by a wall called the sporangium. When the spore germinates, it sends out a delicate thread that grows rapidly in length and forms many branches that soon become covered with mycelium, which the plant grows through. (q) Fig. 272.) One of these threads is termed a hyphae. All the threads together form what is called a mycelium or fungus. The mycelium distinguishes the manner in which it grows, and thus the mycelium plants differ physiologically from the roots and the stems of other plants. +When this mycelium is about two days old, it begins to form the long fruiting stalks which we first noticed. To study them, use a compound microscope and examine two or three of them. +One of the stalks, magnified, is shown in a Fig. 274. It consists of a rounded head, the sporangium, $sp$, supported on a long, + +Fig. 271.--Mycelium of Mucor muscorum. + +Fig. 272.--Sporangium of Mucor muscorum, showing some germinating. + +**Sporangium** + +STUDIES IN CRYPTOGAMS + +189 + +delicate stalk, the sporangiophore. The stalk is separated from the sporangium by a wall which is formed at the base of the sporangium. This wall, however, does not extend straight across the base of the stalk but is bent back upon itself like an inverted pear. It is known as the col- umella, $r$. When the sporangium is produced, the columella disintegrates and allows hundreds of spores, which were formed in the cavity within the sporangium to escape. The part that is left of the fruit is the stalk, with the pear-shaped columella at its summit, $r$. In this way, the spores are protected from the breaking of the sporangium wall are now scattered by the wind and other agents. + +The spores are very small and begin to grow immediately and reproduce the fungus. The others soon perish. + +The mucor may be found in almost any soil itself in all ways indistinctly, but these spores are very delicate and usually die if they do not fall on favorable soil. They are often found in association with another means of carrying itself over unfavor- able season, as winter. This is accomplished by having a long thread-like body called a zygosporus or zygoconid. The zygosporus are formed on the mycelium buried within the substance on which the plant lives. They are very thin. In the fall, two or three that lie near together send out short branches, which grow toward each other and interlace (Fig. 273). These branches then die off, allow- ing the contents to flow together. At this time, however, two other walls are formed at right angles to each other, forming a short section, $r$, from the remainder of the thread. This section now increases in size and becomes a zygoconid (Fig. 274), which is sur- rounded with thickened tubercles. The zygo- conid is now mature and, after a period of time, produces a new sporangium directly or growing out as mycelium. + +The zygosporus of the mucor form one of the most interesting and instructive objects among the lower plants. They are, how- ever, very difficult to obtain. One of the mucors (Opseudomucor) is shown in Fig. 275. + + +A diagram showing a mucor with a sporangium and a zygosporus. + + +**Fig. 274.—MUCOR, showing formation of zygosporus on the right; generat- ing new sporangium on the left.** +274 + +100 +BEGINNERS' BOTANY + +*grandiflora* may be frequently found in summer growing on toad-stools. +This plant usually produces zygosporae that are formed on the aerial mycelium. The zygosporae are large enough to be recognised by the naked eye, but they must be shed and kept for winter study, or the zygosporae may be prepared for permanent microscopic mounts in the ordinary way. + +**Yeast.**—This is a very much reduced and simple fungus, consisting normally of isolated spherical or elliptical cells (Fig. 273) containing abundant protoplasm and prothallus, which is easily observed. It propagates rapidly by budding, which consists of the gradual extrusion of a new cell from the parent one, either cut off at the base by constriction, thus forming a separate organism. Although similar in appearance to yeasts, these fungi are closely related to some of the higher groups of fungi as shown by the method of spore forma- +tion. When grown in water, the yeast cells, with their contents of the cell may form spores outside of the size-like mother cell, thus resembling the sac-fungi to which they belong and which belong. The yeast is a saprophyte, i.e., it lives on dead matter to induce anaerobic fermentation in the media in which it grows. + +There are many kinds of yeasts. One of them is found in the common yeast culture. In the process of manufacture of theseokers, the yeast is given a bath in hot water and then dried and fried into small cakes, each cake containing great numbers of the yeast cells. When the yeast cake is added to the dough, it ferments and gives off alcohol. If this pre- +pared, the yeast grows rapidly and breaks up the sugar of the dough into carbon dioxide and alcohol. This is fermentation. +The yeast is also used in making beer and wine. + +In this bousonised condition the dough is baked; if it is not baked quickly enough, the bread "falters." Shake up a bit of yeast cake in slightly warmed water; the water soon becomes cloudy from the growth of yeast. + +**Parasitic fungi.**—Most of the members are saprophytes. Many other fungi are parasitic on living plants and animals (Fig. 285). +Some of them have complicated life histories, undergoing many changes before the original spore is again produced. The *mildew* (Fig. 286) is one of these; it will serve to illustrate the habits of parasitic fungi. + +The *mildew mildew* (*Ustulina nitida.*).—This is one of the *mildews* of willows. + +A diagram showing a cross-section of a plant cell with a nucleus, cytoplasm, and vacuole. + +STUDIES IN CRYPTOGAMS +191 + +(Fig. 275). These patches consist of numerous interwoven threads that may be recognized under the microscope as the mycetium of the fungus. + +The interwoven threads of this case lives on the surface of the leaf and non- +branching by sending short branches into the +cells of the leaf to ab- +sorb food materials from +the + +Numerous summer-sporers are formed of short, erect branches all over the white surface. +One of these branches is shown in Fig. +276. At certain intervals, at cer- +tain length, the upper part begins to segment or divide into spores which are carried away by the wind. Those falling on other wil- +lows reproduce the fungus there, +while those falling on other trees, +but in the later part of the season +provision is made to maintain the +mycelium. The summer-sporers of +the white patches are closely ex- +amined in July or August, a number being seen in one spot, as in little +shown in Fig. 278. To the naked eye they appear as minute spots, +but when examined with a magni- +fication of two hundred diameters they present a very interesting appear- +ance. They are small hollow spheri- +cal bodies decorated around +the outside with a fringe +of long, silky hairs. The +reeding-sporers of this +mildew are produced in +numbers and are closed with- +in the leaf-leaf. + +Fig. 275. - Colonies of Willow Mildew. + +Fig. 276. - Summer-sporers of Willow Mildew. + +Fig. 277. - Perithecium of Wil- +low mildew. + +Fig. 278. - Perithecium of Wil- +low mildew. + +Fig. 279. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 279. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 280. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 280. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 281. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 281. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 282. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 282. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 283. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 283. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 284. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 284. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 285. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 285. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 286. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 286. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 287. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 287. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 288. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 288. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 289. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 289. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 290. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 290. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 291. - Section through Peri- +thecium of Wil- +low mildew. + +Fig. 291. - Section through Peri- +thecium of Wil- + +191 + +102 +BEGINNERS' BOTANY + +packed in the perithecia. They do not ripen in the autumn, but fall to the ground with the leaf, and there remain securely pro- +tected among the dead foliage. The following spring they mature +and give rise to the new crop of perithecia. They are then +ready to attack the unfolding leaves of the whiter and repeat the +work of the summer before. + +The wheat rust—The development of some of the rusts, as the +common wheat rust (Puccinia graminis), is even more interesting +amongst the parasites than that of the black spot of millet. Wheat rust is also a true +parasite, affecting wheat and a few other grasses. The mycelium here +can be seen only by means of a microscope, for it consists of threads which are present within the host plant, mostly in the leaf sheath and stem. These +threads also send short branches, or +haustoria (Fig. 135), into the neigh- +bouring cells of the host. + +The rhizogenous wheat rust is produced in late summer, when +the wheat is ripening. The spores break through the epidermis of +the wheat stalk (black-stand stage). They grow out into long, conical +spores (Fig. 280), from the ends of numerous crowded mycelial strands just beneath the epidermis of the host. The individual mycelial strands can be well +studied only with a microscope of high power +(x about 400). They are brown two-celled bor- +dowhich are often joined together. When these +the resting or winter-spores, they are termed *leu- +teospores* ("completed spores"). Usually they do +not fall, but remain in the soil during winter. +The following spring, when the wheat puts forth a rather stout thread, which does not +grow more than several times the length of the +spore, another thread grows up from this germ tube, promycelium, now becomes divided into four cells by cross walls, which are formed +from the end of the germ tube. This gives rise to a short, pointed branch which, in the course of a few hours, forms at its summit a single spore called a *sporangium*. This in turn germinates and produces a mycelium. In Fig. 281 a germinating teleteospore is drawn to show the promycelium, $A$ divided into four cells, + +Fig. 280.—The wheat rust. +TAINTING TELETEOSPORE OF WHEAT RUST. + +Fig. 281.—The teleteospore of wheat rust. +TELETEOSPORE OF WHEAT RUST. + +STUDIES IN CRYPTOGAMS +193 + +each producing a short branch with a little cpe- +ridium, 1. + +A very remarkable circumstance in the life +history of the wheat rust is the fact that the myc- +elium produced by the spore-dima can live only +in burberry leaves, and it follows that the +fungus has to pass through two stages before the spores +finally perish. Those which happen to lodge on a +burberry leaf produce a mycelium which, after +growing a mycelium that enters the burberry leaf and +grows within its tissues. Very soon the fungus +produces a new kind of spores on the burberry +leaves, these being called teliospores, and they +are formed in long chains in little fringed cups, or +ecidia, which appear in groups on the lower side +of the leaf. The cup-like structures are called +ecidia, which are termed cluster-cups. In Fig. 284, +is shown a cross-section of one of the cups, contain- +ing the teliospores, which are seen in the tissues. +The ecidiopores are formed in the spring, and after they +have been set free, some of them lodge on wheat or other grasses, +where they germinate immediately. The germ-tube enters the + +![Image of a leaf of burberry with teliospores] + +Fig. 283.--LEAF OF BURBERRY WITH TELIOSPORES. + +![Image of a section through a cluster-up of burberry leaf] + +Fig. 284.--SECTION THROUGH A CLUSTER-UP OF BURBERRY LEAF. + +leaf through a stomate, whence it spreads among the cells of +the plant tissue. In summer (when the "light" +spores, "rol-rust" stage) are produced in a manner similar to the teleutospores. These are capable of germinating immediately, + +193 + +104 +BEGINNERS' BOTANY + +and serve to disseminate the fungus during the summer on other wheat plants or grasses. Late in the season, teleotospores are again produced by the wheat and grasses. + +Many rusts besides Puccinia graminis produce different spore forms on different plants. The phenomenon is called heteromycosis, and was first shown to exist in the wheat rust. Curiously enough, no previous writer had noticed this fact, and it was not until 1875 that the English botanist, W. H. Smith, made the discovery. He found that the rusts of wheat cause wheat to blight long before science explained the relation between these two plants. This fact has been known since 1875, but it has never been done for many other rusts on their respective hosts, by sowing the zygothecae on healthy wheat plants and thus producing + +A diagram showing the life cycle of a parasitic fungus. It shows the ascus (spore-producing structure) of a fungus growing on a bean pod, with a cross-section of the pod showing the presence of the fungus within it. The diagram also shows the spores being released from the ascus and falling onto a leaf of another plant, where they germinate and grow into new fungal structures. + +Fig. 28.-How a PARASITIC FUNGUS WORKS. Anthriscose on a bean pod (left), with a cross-section showing the fungus within. Spores from the ascus (right) fall upon a leaf of another plant, where they germinate and grow into new fungal structures. + +the rust. The *cider apple* is another rust, producing the curious swellings often found on apple trees and similar trees. In the spring the teleotospores come out from the "apple" in brownish yellow masses. It has been found that these attack various fruit trees, producing swellings on their leaves. Fig. 28 explains how a parasite fungi works. + +**Puffballs,** mushroom-like, toothless, and shaggy **fungi**.--These represent what is called the higher fungi, because of the size and complexity of the plant body as well as from the fact that they seem to stand at the end of one line of evolution. The mycelial threads grow together in extensive strands in rotten wood or in the soil, and send out large complex growths of mycelium in con- + +STUDIES IN CYTROTOMS + +mention with which the species are born. These neural parts are the only ones which are usually seen, and which constitute the "nuchal room" part (Fig. 131). +Only axonal spires (ha- +mata) are visible on the +and on short stachys (basidia) +(Fig. 280). In the periph- +ery of the "nuchal room" +and constitute a large part +of the "smoke." In the +endoderm and tentacles +they are borne by cells +in the shelf fang (Fig. 134) +on the walls of numerous pores +in the "nuchal room." The +columella of these shelf fungi +frequently lives and grows +for a long time in the +substratum before the +visible fruit bodies are sent +out into the water. The +decay is caused by such +growth, and the damage in +the fruiting bodies appears. For other ac- +counts of mushrooms, see Chapter XIV. + +LICHENS + +Lichens are so common everywhere that the attention of the student is sure to be drawn to them. They grow on rocks, trees, walls (Fig. 135), ed- +fences, and on the earth. They are thin, usually gray ragged objects, ap- +parently composed of two plants, but it is too difficult for beginners, but a few words of explanation may be useful. +I have often been asked what is supposed to be a distinct or separate division of plants. They are now known to be co- +lumnic, each species of which is a con- +stituent of a fungus and a green alga. +The thallus is ordinarily made up of fun- +gus mycelium or tissue within which +the green alga is enclosed and dis- +tributed. The result is a growth unlike +either component. This association of + +Lichen on Oak Tree. +195 + +**FIG. 135—LICHEN ON AN OAK TREE. [A species of Physcia.]** + +196 +BEGINNERS' BOTANY + +algæ and fungus is usually spoken of as *sympistis*, or mentally +helpful growth, the algæ furnishing some things, the fungus others, +and both being mutually dependent on each other for their nutriment. +But this union is not always necessary, for many fungi can live +without the alga. By others this union is considered to be a mild form of parasitism, in which the fungus profits at the expense of the alga, but does not destroy it. It is generally supposed that each component is able to grow independently, and that under such conditions the algal cells seem to thrive better than when +mixed with the fungus. + +Lichens propagate by means of *septaria*, which are tiny parts separated from the body of the thallus, and consisting of one or more algae, often overgrown with hyphae. These are readily observed in many lichens. They also produce minute *ascomycetes*, which are always the product of the fusing elements, and which reproduce the lichen by germinating in the presence of +algæ cells, and forming new thalli. + +Lichens are found in the most inhospitable places, and, by means of acids which they secrete, they attack and slowly dis- +sociate rocks. The following description will show how to cut the thallus with a sharp razor and examining under the compound microscope, it is easy to distinguish the two components in many lichens. + +**LIVERWORTS** + +The liverworts are peculiar flat green plants usually found on wet cliffs and in other moist, shady places. They frequently occur in greenhouses where the soil is kept constantly wet. + +One of the commonest liverworts is *Marchantia polymorpha*, two plants of which are shown in figs. 288 and 289. The thallus consists of a ribbon-like thallus that creeps along the ground, becoming repeatedly forked as it grows. The end of each branch + +Figs. 288. +Figs. 289. + +PLANTS OF MARCHANTIA. + +STUDIES IN CRYPTOGAMS + +197 + +It is always conspicuously notched. There is a prominent midrib extending along the centre of each branch of the thallus. On the under surface of the thallus, and especially along the midrib, there are numerous rhizoids which serve the purpose of rooting, absorbing nourishment from the earth and holding the plant in position. The upper surface of the thallus is divided into minute rhombic areas, each of which contains a single eye. Each of these areas is perforated by a small breathing pore, situated just beneath the epidermis. This space is surrounded by a chlorophyll-bearing cell, or layer of white substance, in rows on either side of the cavity (Fig. 290). The delicate assimilating tissue thus is thus brought to close communication with the outside air through this little black protuberance. + +At various points on the midrib are little cups containing small green bodies. These bodies are buds of genoma which are outgrowing from the parent plant. When they have grown up they become loosened and are then dispersed by the rain to other places, where they take root and grow into new plants. + +The antheridioles or stalked bodies of marchantia are the peculiar stalked bodies shown in Figs. 283, 285. These are termed archegoniphores and antheridioles or receptacles. Their structure is shown in Fig. 291. The antheridioles are so minute that they can be studied only with the aid of a microscope magnifying from 100 to 400 times. Enlarged drawings will guide the pupil. + +Fig. 290.—SECTION OF THALLUS OF MARCHANTIA. Somewhat at a. + +Fig. 291.—SECTION THROUGH ANTHERIDIOPHORE OF MARCHANTIA, showing antheridia. One antheridium more magnified. + +The antheridioles are fleshy, lobed disks borne on short stalks (Fig. 291). They contain numerous antheridia, some being scarcely visible to the naked eye. However, a section of the disk, such as is drawn in Fig. 291, shows that the pores lead into oblong caviities. + +Fig. 290a.—SECTION OF THALLUS OF MARCHANTIA. Somewhat at a. +Fig. 291a.—SECTION THROUGH ANTHERIDIOPHORE OF MARCHANTIA, showing antheridia. One antheridium more magnified. + +198 + +tics in the receptacle. From the base of each cavity there arises a thick, club-shaped body, the antheridium. Within the anther- +idium are formed many sperm-cells which are capa- +ble of fertilizing the eggs. These are produced by the +hairs or cilia attached to them. When the antheri- +dium is mature, it bursts and allows the citrated +spores to escape (Fig. 293). The archegoniphores are also elevated on stalks (Fig. 293). Instead of a simple receptacle, +the antheridium is a long, slender, thread-like body. +The under side of the ray, between delicately fringed curtains, peculiar flask-like bodies, or arche- +gonia, are situated. The archegonia are not visible to the naked eye. They can be studied with the microscope (x about 400). One of them much magnified is represented in Fig. 293. Its primary cell is a large egg-cell, surrounded by a rounder ray, b, including a large free cell—the egg-cell. + +We have seen that the antheridium at maturity discharges its spermo-cells. These swim about in the water provided by the dew and rain. Some of them finally find their way to the antheridium of another plant and there are fertilized, as pollen fertilizes the ovules of higher plants. + +After fertilization the egg-cell develops into the sporophore of sporogonium. The mature sporophore capsules may be seen in Fig. 293. They consist of two parts, a lower part, which is still alive, and the upper part which is imbedded in the time of the receptacle, from which it derives the neces- +sary nutrition for the development of the sporogonium. + +At maturity the sporogonium is ruptured at the apex, setting free the spheri- +cal spores together with numerous filaments having no other function than to scatter these filaments are called elaters. When drying, they exhibit rapid movements by means of which the spores are scattered. The spores germinate and again produce the tissues of Marchantia. + +Fig. 293.—ARCHE- +GONIA, WITH SPORO- +GENIA, OF MARCHAN- +TIA. +Fig. 294.—SPORES AND ELAYERS OF MARCHANTIA. + +STUDIES IN CRYPTOGAMS +199 + +Mosses (Bryophyta) + +If we have followed carefully the development of marchantia, the study of one of the mosses will be comparatively easy. The mosses are more familiar plants than the liver-worts. They grow on trees, stones, and on the soil, and are found in all parts of the world. The common larger mosses, known as Polytrichum commune, are shown in Fig. 295. This plant grows on rather dry soils, mostly in the borders of open woods, and on rocks and other hard beds. In dry weather these beds have a reddish brown appearance, but when moistened they form beautiful green cushions. This colour is due, in part at least, to the colour of the old stems and leaves, and in the second instance to the action of the green living cells. + +The inner or upper surface of the leaf is covered with thin, longitudinal ridges of delicate cells which contain chlorophyll. These cells are shown in cross-section in Fig. 296, at dots on the left. All the other tissues of the leaf consist of thick-walled, corky cells which do not allow moisture to penetrate. When the air is moist the green leaves spread out, exposing the chlorophyll cells to the air, but in + + +A small illustration showing a section of a leaf of Polytrichum commune. + + +Fig. 295.--POLYTRICHUM COMUNE. +a, fertile plant, one on the left is fresh; +b, submerged plant. + + +Fig. 296.--SECTION OF LEAF OF POLYTRICHUM COMUNE. +not allow moisture to penetrate. When the air is moist the green leaves spread out, exposing the chlorophyll cells to the air, but in + +dry weather the margins of the leaves roll inward, and the leafvein fold closely against the stem, thus protecting the delicate assimilating tissues. + +The antheridia and archegonia of polypartrichum are borne in groups at the ends of the branches on different plants (many mosses have only one organ), and are usually roundly or ovate-rounded by involution of characteristic leaves termed *perichaeta* or *perichordal leaves*. Multicellular hairs known as *paraphyses are scattered over the surface of these leaves, and with the organs borne within them are called receptacles, or, less appropriately, "moss flowers." As in marchantia, the organs are very minute and must be highly magnified to be studied. + +The antheridia are borne in groups on the antheridial plants (Fig. 297). + +They are much like the antheridia of marchantia, but they stand free and are not sunk in cavities. At maturity they burst and allow the sperm cells or *sporophores* to escape. The *archegonium*, when the receptacles have fulfilled their function, is the stem con- taining a single egg cell, which is enclosed in the cup (see Fig. 295). The arche- gonia are borne in other receptacles similar to those of Marchantia. They are like Marchantia except that they stand erect on the end of the branch. + +The *spore-case* which develops from the fertilized egg is shown in a, b, Fig. 293. It consists of a long, brown stalk bearing the spore-case at its summit. The base of the stalk is imbedded in the end of the moss stem by which it is nourished. The expanded part of the stalk is called the *sporangium*. The calyptera is really the remnant of the archegonium, which, for a time, increases in size to accommodate and protect the young growing spore. The spore-case is closed by a cover called the *spore-case lid*. The mouth of the capsule is closed by a circular lid, the *episporeum*, having a conical projection at the center. + +The entire spore-case is filled with spores, each bearing a fringe of sixty-four teeth guarding the mouth of the capsule. This thing of teeth is known as the *peristome*. In most mosses the teeth extend outward from the margin of the case; in some they bend outward, and upon drying curve inward toward the mouth of the capsule. This motion, it will be seen, serves to disperse these spores over a wide area. + +Not the entire spore-case is filled with spores. There are no claters, but the centre of the capsule is occupied by a columnar + +Figure 297 - Section through a receptacle of Polypar- trichum showing antheridia and paraphyses. +200 +BEGINNERS' BOTANY + +STUDIES IN CYPTOGAMS + +201 + +strand of time, the coleolus, which expands at the mouth into a thin, membranous disk, closing the entire mouth of the capsule except the narrow annular chink guzneted by the teeth. In this most curious point of the two species, the teeth are placed at the origin of the strand, allowing the pores to silt out through the spaces be- +tween them. + +In these the spores germinate they form a green, +branched thread, the prothallus. This gives rise directly to moss plants, which appear as little buds on the surface of the soil. The prothallus have sent their little rhizoids into the earth, the pro- +tonema dies, for it is no longer necessary for the survival of these plants, and the moss plants grow independently. + +*Funaria* is a moss very common on damp, +open soil. It forms green patches of small fine leaves from which arise long brown stalks termin- +ally with a small cup-shaped head. The plant's struc- +ture is similar to that of *Polytrichum*, except the +absence of plates on the under side of the leaves, +the continuous growth of the stem being produced +continuously from the base of each internode rather than by dicious re- +ceptacles, and nearly globular asymmetrical calyptes. + +**Equisetum**, or **Horsetails** (Pteridophyta) + +There are about twenty-five species of equisetum, constituting +the only genus of the unique family Equisetaceae. Among these *E.* +arvensis (Fig. 29) is common on clayey and stony soils. + +In all species of *Equisetum* reproduction by spore +production is performed by separate shoots from an underground rhizome. The fertile branches appear early in spring. The stems, which are covered with a dense covering of short, +furrowed internodes, each sheathed at the base by a circle of scale leaves. The sheaths are of a pale yellow colour. +They contain no chlorophyll, and are nourished by the food stored in the rhizome (Fig. 295). + +The spores are formed on specially developed fertile leaves or +sporophylls which are connected by a stalk to the end of +the stalk (Fig. 30). A single sporophyll is shown at left. It consists of a short stalk expanded into a broad, mushroom-like head. Several large *gonangia* are borne on its under side. The +spores formed in the sporophylls are very interesting and beautiful + +A diagram showing the structure of *Equisetum.* +**FIG. 295—** **Po-** +**GEOGRAFICA,** + +202 +BEGINNERS' BOTANY + +objects when examined under the microscope (x about 300). They are spherical, green bodies, each surrounded by two spiral bands attached to the spore at their intersection, z. These bands exhibit hygroscopic movements by means of which the spores be- +come enclosed in a protective case, the prothallus, within the plant, as we shall see. All the spores are alike, but some of the pro- +thallus grow to a greater size than the others. The large prothallus produces only fertile shoots, while the smaller ones produce both sterile and fertile shoots. The fertile shoots are much like those of ferns, and fertiliz- +ation is accomplished in the same way. Since the prothallus are usually diclinous, the special attachment of the spiral bands, holding the spores together so that both kinds of prothallus in one prothallus will be easily understood. As in the fern, the fertilized egg divides into two cells. + +The sterile shoots (z, Fig. 209) appear much later in the season. They give rise to repeated whorls of angular or furrowed branches. The leaves are simple, linear, and alternate with those of the fertile +rods. The stems are provided with chlorophyll and act as +resisting tissue, nourishing the rhizome and the fertile shoots. +Nutrient is also stored in special tubers developed on the rhi- +zome. + +A diagram showing the structure of a prothallus. + +FIG. 209. - EQUISETUM ARVENSE, +at, sterile shoot; f, fertile shoot showing the spike at e; A, sporophyte, with sporangia; +A', sporangium. + +203 + +STUDIES IN CRYPTOCAMS +203 + +Other species of equisetum have only one kind of shoot—a tall, hard, leafless, green shoot with the spike at its summit. Equisetum stem are full of silica, and they are sometimes used for scouring floors and utensils; hence the common name "scouring rush." + +**Isoetes (Tierodophyta)** + +*Isotes* or *quillwort* is usually found in water or damp soil on the edges of ponds and lakes. The general habit of the plant is seen in the figure. It consists of a short, perennial stem bearing numerous erect, quill-like leaves, which are covered with silica. + +The plants are commonly mistaken for young grasses. + +Isotes has two kinds of spores, large roughened ones, the macrospores, and small ones of a smooth surface formed in sporangia borne in an excavation in the expanded base of the stem. The macrospores are formed on the outer and the microspores on the inner leaves. A prolongation of the stem, a leaf sheath, at the tip is partially covered by a thin membrane, the *veil*. The minute triangular structure lying within the wall of the sporangium is called the *ligula*. + +The spores are liberated by the decay of the sporangia. They form rudimentary prothalli of two kinds—prothalli with a prothallial leaf with auricles, while the macrospores produce prothalli without auricles. This liberation takes place as in the mosses or liverworts, and the fertilized egg-cell, by continued growth, gives rise again to the isotea plant. + +**Club Mosses (Tierodophyta)** + +The club-mosses are two trailing plants of moss-like looks and habits, although more closely allied to ferns than to true mosses. Except one genus in Florida, all the club mosses belong to the + +A diagram showing the habit of a typical member of this class, showing sporangium, rhizome, and ligula. +b + +204 +BEGINNERS' BOTANY + +genus *Lycopodium*. They grow mostly in woods, having 1-nerved evergreen leaves arranged in four or more ranks. Some of them make long strands, as the ground pine, and are much used for Christmas decorations. The leaves are usually in two rows, borne in 1-celled sporanges that open on the margin into two valves. The sporangia are borne in some species (Fig. 301) + +**Fig. 301.—A Lycopodium with sporangia in the axils of the foliage leaves. (Lycopodium clavatum.)** + +as small yellow bodies in the axils of the ordinary leaves near the tip of the shoot; in other species (Fig. 301) they are borne in the axils of small scales that form a carkin-like spike. The spores are very numerous, and they contain an oil that makes them inflammable, and this property has been known to the ancients. + +The plants grown by florists under the name of lycopodium are of the genus *Selaginella*, more closely allied to *naiades*, bearing two kinds of spores (interspores and intersporangia). + +INDEX + +Aborted seeds, 266. +Achillea, 125. +Accessory fruit, 354, 160. +Adhatoda, 178. +Adventitious roots, 303; 304; 106. +Aerial roots, 304. +Aegopodium, 188. +Air plants, 25. +Alchemilla, 189. +Algus, 179, 183; 195. +Alisma plantago-aquatica, 179. +Anemophila, 149. +Anemone plant, 121. +Anthyllis, 186. +Anthurium, 186. +Aquilegia, 179; 200; 209; 202; 203. +Apical dichotomous, 190. +Aphidius aphidicola, 293; 294; 295; 297; 298. +Arum kamtschaticum, 149. +Arum italicum, 149. +Aristolochia, 179. +Aristolochia clematitis, 179. +Aristolochia rotunda, 179. +Aristolochia versicolor, 179. +Baccharis halimifolia, 305. +Baccharis pilularis, 305. +Barbarea stricta, 54. +Barbus barbus, 66. +Barbus caninus, 30; 394. +Berry, ssp., 157. +Bromus arvensis, 157. +Brace calyx, c.8. +Brassica oleracea var. capitata, c.8. +Branchiostoma fumigatum, c.8. +Bryophyllum pinnatum, c.83. +Budling, t22; t23. +Bud peeling off leaf petiole, t23; flower, t25; flower bud, t25; flower bud opening up to become a leaflet, t25; flower bud opening up to become a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet and then becoming a leaflet +Candollea, b.5; b.6; +Capitula, t54; +Carbohydrate(s), t54; +Carboxyl group(s), t54; +Carboxyl fluoride(s), t57; t58; t59; +Carotenoid(s), t59; +Caryophyllaceae family(s), t60; +Cactus(s), b.4; +Cauliflower(s), b.4; +Castanea mollissima subsp. mollissima (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativa subsp. sativa (L.) Bunge ex Fisch., b.4; +Castanea sativ + +206 +INDEX + +Dactyloloides, 20. +Dactylochlamys stricta, 67. +Dactylus, 25. +Digitata, 24. +Lindera, 184. +Deciduous, 3, 179. +Dispersal of oecum, 172. +Dioecious, 172. +Dolichos, 35, 106. +Dolichos, 106. +Lecythus, 168. + +Ecology, 24. +Eclipta, 198. +Euphorbia, 180. +Euphorbia, n.s., 180. +Euphorbia, n.s., 180. +Euphorbia, n.s., 180. +Euphorbia, n.s., 180. +Euphorbia, n.s., 180. +Environment, 146. +Eucalyptus, 303. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Eucalyptus, n.s., 65. +Fermentation, 199. + +Fertilization, 144; c. apicalis, +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apicalis; +c. apicalis; c. apICALIS +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars +Cultivars + +Flowering plant + +INDEX +207 + +Laccolidalis discorsis, 166 +Lumber, 65. +Lygodium, 204. +Marcescentes, 293, 294. +Marcescentes, 293, 294. +Medullary ray, 64. +Morphophyllum, 187. +Micropyle, 21, 96. +Microspore, 21, 96. +Microspore, 293. +Microspore, 293. +Mistful family, 339. +Nidulaceae, 190. +Nidulaceae, 190. +Nidulaceae, 190. +Monocotyledons, 20, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, 75-163. +Monocotyledons, 134, +Illustration of a plant with long leaves and a central stem. +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae +Nectariaceae + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata + +Quercus serrata. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of a plant with long leaves and a central stem. + +Illustration of an insect on the leaf underside. The insect has elongated antennae that curve upwards at the tips. It also has two large compound eyes on its head. The body is segmented into three parts: the head (with the eyes), the thorax (which appears to be slightly larger than the head), and the abdomen (which is longer than the thorax). The legs are visible but not detailed. The background shows part of the leaf surface. The insect's wings are not visible in this view. This illustration is likely from the family Hymenoptera (ants or wasps) due to the shape of the antennae. The insect could potentially be an ant or wasp species. The leaf underside is shown clearly enough to identify the insect's features without any confusion about what it might be. The insect's position on the leaf suggests it is either resting or moving slowly. The leaf itself appears to be healthy but not overly detailed. The overall scene gives an impression that this is an outdoor setting during daylight hours. The insect's presence on the underside suggests it may be feeding on nectar or pollen from the flowers below. This illustration is useful for identifying insects on plants in their natural habitat. It can help in understanding their behavior patterns or ecological roles within the ecosystem. This image could be used in educational materials such as field guides or nature documentaries to illustrate different types of insects found in various habitats. It could also be used in scientific research papers to describe the morphology or behavior patterns observed in these insects. Additionally it could be used in art projects or illustrations for children's books to teach them about different insects in their environment. This image provides valuable information for both educational purposes as well as for artistic expression related to nature studies.", "The illustration depicts an insect on the underside of what appears to be an oak leaf. The insect has elongated antennae that curve upwards at the tips. It also has two large compound eyes on its head. The body is segmented into three parts: the head (with the eyes), the thorax (which appears to be slightly larger than the head), and the abdomen (which is longer than the thorax). The legs are visible but not detailed. The background shows part of the leaf surface. The insect's wings are not visible in this view. This illustration is likely from the family Hymenoptera (ants or wasps) due to the shape of the antennae. The insect could potentially be an ant or wasp species.", "The illustration depicts an insect on the underside of what appears to be an oak leaf. The insect has elongated antennae that curve upwards at the tips. It also has two large compound eyes on its head. The body is segmented into three parts: the head (with the eyes), the thorax (which appears to be slightly larger than the head), and the abdomen (which is longer than the thorax). The legs are visible but not detailed. The background shows part of the leaf surface. The insect's wings are not visible in this view. This illustration is likely from the family Hymenoptera (ants or wasps) due to the shape of the antennæ.", "The illustration depicts an insect on the underside of what appears to be an oak leaf. The insect has elongated antennæ that curve upwards at the tips. It also has two large compound eyes on its head. The body is segmented into three parts: the head (with the eyes), the thorax (which appears to be slightly larger than the head), and the abdomen (which is longer than the thorax). The legs are visible but not detailed. The background shows part of the leaf surface. The insect's wings are not visible in this view.", "The illustration depicts an insect on the underside of what appears to be an oak leaf. The insect has elongated antennæ that curve upwards at the tips. It also has two large compound eyes on its head. The body is segmented into three parts: the head (with the eyes), the thorax (which appears to be slightly larger than the head), and the abdomen (which is longer than the thorax). The legs are visible but not detailed.", "The illustration depicts an insect on the underside of what appears to be an oak leaf. The insect has elongated antennæ that curve upwards at the tips.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside of what appears to be an oak leaf.", "The illustration depicts an insect on the underside + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
208DYDEX
Scape, 163.Survival of filbert, 7.
Scouting rush, 203.Swami-eyes, 296.
Scratchers, 185.Symbiosis, 296.
Scratchers, 185; 180; cost, 254.Synapsis, 297.
Scrubjacks, 294.Tectonoporus, 192.
Cerambycidae, 8; artificiali, 8;Tectonops, 192.
Scrub, 133, 160.Tectonops, 192.
Cyrtis, cupride, 266.Tectonops, 192.
Seeds, 77.Tiburna, ssp. tiburnae,
Sirif fungus, 194.Tiburna, ssp. tiburnae,
Sieve tubes, 66.Tiburna, ssp. tiburnae,
Silicea, 177.Tiburna, ssp. tiburnae,
Silique, 177.Tiburna, ssp. tiburnae,
Sol., 49; 47.Tiburna, ssp. tiburnae,
Sol., ssp. tiburnae,Tiburna, ssp. tiburnae,
Sori, 177; rps.Tiburna, ssp. tiburnae,
Squids, rps.Tiburna, ssp. tiburnae,
Synapsis, rps.Tiburna, ssp. tiburnae,
+ + +1 + +Il + +CLOSSARY + +capsule. A pod consisting of two or more carpels or ports, usually opening naturally. +carbohydrate. The compounds of the starch and sugar class. +caryopsis. One part or member of a compound pistil, or a simple pistil itself. +citron or amont. A raceme-like or spike-like flower-cluster that falls away after flowering or fruiting, as of willows and staminate flowers of certain plants. +cestifruit. From the inside out as a flower-cluster of which the inside, terminal, or uppermost flowers open first; a determinate cluster. +cerebriform. From the outside in; as a flower-cluster of which the outer flowers open first; an indeterminate cluster. +chlorophyll. Leaf green. Chlorophyll is the pigment that gives the leaves their characteristic green color. +cladophyll. Stems that look like leaves, and function as leaves, as in azarapa and the 'florist's' smilax. +deliquescent. Applied to small flowers, usually hidden beneath the earth, but opening at night to form floral envelopes, and are self-fertilized; also to self-fertilization in flowers that do not open. +complete flower. Have all the parts -- calyx, corolla, stamina, pistil, receptacle. The inner row or series of flower-leaves, usually colored, and at the 17th-18th stage. It may be all one plant or all many pieces. +corolla. A flatish flower-cluster in which the outermost flowers open first. +cyclamen. A leaf of the embryo--seed-leaf. The embryo may have one cotyledon (monocotyledon), or two cotyledons (dicotyledon), or sometimes more than two. +cross-fertilization is facilitated by means of pollen produced in another flower. +ceryogamia. One of the group of flowerless or non-seed-bearing plants, as a fern, fungus, moss, seaweed. +cotyledon. A shoot planted in soil or water for the purpose of making a new plant. +cyme. A flatish or broad flower-cluster in which the innermost or terminal flowers open first. +decemseptem. Said of branches or stems that lap or lie over on the ground. +decrescent. Said of a leaf that runs down on the stem, thereby not having a distinct petiole. +dehiscent. The mode of opening, as of a seed-pod or an anther. + +Glossary + +deliquescent. Said of trees in which the leader or main trunk disappears at the tree-top, forming into several or many main branches. + +determinate. The condition when stamens and pistils in the same flower mature at different times; this prevents or hinders self-pollination. See *predeterminate* and *predeterminate*. + +diclinous. Said of flowers that are imperfect, -- lacking either stamens or pistils. + +dicotyledon. Having two cotyledons or seed-leaves. + +digestion. Change in the food material whereby they may be trans- ported to other parts of the body. *S* starch is changed into sugar in the plant by a process of digestion. + +dimorpha. Of two forms; as flowers that bear two kinds of stamens. + +diversion. Said of plants that bear stamens and pistils in flowers on different stems. + +droop. A feebly perky or fruit, containing a relatively large stone or pit, as peach, cherry, plum. + +drupe. A fruit with a stone, particularly one consisting part of an aggregate pith, as a drupe of raspberry. + +embryo. The dormant plantlet comprising part of the seed. It is enclosed within the seed-coats. Its parts are the caulete (or stem), cotyledons (or seed-leaves), and radicle (or root). It may be stored in the embryo, or around the embryo (endosperm). + +endoge. A plant of the monocotyledon class, not charging in diam- ter by means of outside rings; as palms. All grasses and lilies and orchids are endoge genera of this kind. Now used, if at all, to express a general class of growth rather than a class of plants. + +see *endophyte*. + +endophyte. The food material that is packed around the embryo (cotyledon) or endosperm in the seed. + +entomophilous. Said of flowers that are pollinated by insects. + +environment. The surroundings; or the conditions in which a plant or animal lives. The environment comprises the soil, climate, and the influence of other plants and animals with which or among which the plant or animal grows. + +ephiphytum. The internode or "joint" above the seed-leaves or cotyledons. + +ephlophorus. The upper layer or part of the cortex of the stem. + +filial. Said of seeds (as those of orchids) that have their cotyledons or seed-leaves raised above ground in germination. See *epigynous*. + +epiphytic. A plant that grows on another plant, or on other objects above ground, but which does not derive much if any of its nouri- ment from its host; an epiphyte. + +iii + +iv +GLOSSARY + +excurrent. Said of trees (as firs and spruces) in which the main trunk or leader continues through the tree-top. + +cageus (see also Cephalocera). Of the dicotyledon class, the stem enlarging by external layers of tissue, as in the apple. + +fertilization takes place in the flower when a pollen nucleus and an eggcell nucleate unite in a forming ovule. + +flowering-plant. A plant with a flower composed of stipe tubes, mechanical fibre and vessels or cells. + +filament. The stilk part of a stem. + +follicle. A single-cavity fruit or pod opening along its inner edge. + +Semicircular or cup-shaped fruit. + +fruit. In botany, the ripened ovary with the attached parts. All flowering plants, therefore, produce fruits. The term is also used for the ripened reproductive bodies of flowerless plants. + +fruitless. Not bearing fruit; without fruit; barren. + +function. What a plant or an organ does; how it works. + +gametophyte. A cell or nucleus that takes part in fertilization. + +gametophytic. The stage of the plant (as the prothallus) that bears or produces gametes. + +gonocarpous. Said of a cordylis with the petals united. + +gonocarpous. Said of a calyx with the sepals united. + +generation. The entire life period of a plant. + +gonopodium. The male organ of reproduction at the action of the roots. + +gonodrome. A dense globular or oblong flower-cluster in which the upper or inner flowers open first. + +graft. A cutting inserted in another plant for the purpose of having it grow on it. + +gymnosperm ("naked seed"). A name applied to a group of plants (pines, spruces, cedars, and the like) in which the seeds are not contained in a fruit. + +head. A very dense globular or oblong flower-cluster in which the outer flowers open first; often applied to any dense flower-cluster, herb. A plant that never becomes woody and that dies to the ground, or dies back to the base each year. + +lilium. The spot or spot where the seed was attached to its stalk. + +lip. The fruit of the rose, which is a hollowed tube containing the dry fruits or "seeds." + +homogamous. Same sex, or sex, in origin or structure. Thus, a ten- +dril of grape is homogamous with a branch; a tendril of grape is analogous to a tendril of pen (similar in function), but not homolog- +ous, for one represents a branch (or flower-cluster) and the other represents a leaf. +5 + +GLOSSARY V + +**Brot.** A plant or animal on which another organism grows or feeds. +**brucha (plural bruchus).** The threads of the mycelium of a fungus. +**deceptiv.** The fruiting body of a fungus that is not easily recognized as such. +**fagoparum (plural fagoparums).** The seeds of certain plants in which the coenobial remains under ground in germination. See *epical.* +**imperfect flowers:** lack either stamens or pistils. +**incomplete:** lacking one of the parts or series, as the calyx, corolla, stamens, or pistil. +**interterminate.** See *certificant.* +**industrious.** The scale or leaf covering a scurf, in ferns and allied plants. +**inferior leaves:** the lower leaves; a word of borrowing (page 66), but some times used in the sense of a flower-chaser. +**involucre.** A sheath or cup of leaves or bracts beneath a flower or a cluster of flowers: sometimes looks like an outer or extra calyx. +**jewel-fingered:** have several members of one or more of the series unlike their fellows. +**key fruit.** See *sementa.* +**labiate:** Lipped; that is, divided into parts, as the lips of a mouth. +**Naked-leaf:** Plants that are divided into two pairs. +**lateral.** On the side: as a flower or leaf borne on the side of a shoot rather than at its end. See *termini.* +**Ligule.** One of the divisions of a leaf composed of laminae. +**ligulate:** Lipped, but narrowing along both edges. In some cases, as in penst., the pod does not actually open. +**lepidous plants:** those that bear lemmas or true pods, as peas, beans, etc.; also, the perianth, petal, lobe, petiole, leaf-blade. +**lenticular:** Very rounded or conical; corby cleftuations on young twigs, marking the place of former twig infections. +**locule.** One cavity or "cell" in a pistil or anther. +*Localized infection:* When the corpus of complications occur between the partitions. + +**mesophyll.** The parenchyma in the leaf. +**micropyle.** The place on the seed at which the pollen tube enters, +when it has to pass through an imperforation (see *place*). +*monocotyledon.* Having one cotyledon or seed-leaf. +*mosses.* Said of plants that bear the stamens and pistils in different flowers on the same plant. +*mycetoid.* The vegetative part of a fungus, composed of threads or hyphae. +*mycorrhizal.* A root covered with or bearing a fungus that aids the root in securing nutrients from the soil. +*nucellus.* Said of flowers that lack envelopes (calyx and corolla). + +vi +GLOSSARY + +nectar. A cup, sac, or place in the flower in which nectar (or "honey") is borne. + +necrosis. The passing or diffusion of liquids or gases through mem- +branes. + +necrosis. The longer enlarged part of the pistil, containing the ovules or forming seeds. + +ovule. The young or forming seed. + +anther. The male part of a flower that arises from the base of the +leaf (top of petiole), or of leaves similarly arranged. + +pistil. A branching raceme. The flower or outer flowers open first ; but the base is often used loosely. + +spadix. A long, cylindrical, leafy or scale-like structure on the top of a dry fruit, +particularly of a fruit (or "seed") of the Composite or sunflower family. + +parasite. An animal or plant that lives on a living host (as on a plant +or an animal) taking its food from the host. See saprophyte. + +parenchyma. The general underlying tissue, from which other tissue arises. + +petiole. Stem of a large flower in a cluster. + +peduncle. A flower stem supporting a solitary flower or a cluster of flowers. + +perennial. A plant that lives more than two years, as most grasses, +deciduous trees, and shrubs, but some plants live only a short time. +perfect flowers bear both stamens and pistils. + +irregular. A irregular array, without connecting attached parts. + +personate. Masked; that is, so formed as to suggest a masked face, +in bilaterally symmetrical leaves lower tip. + +petal. One of the parts of leaves of the corolla. + +petiole. Stem or stalk of a leaf. + +pedicel. Stem of a kind of peduncle. + +plagiocephalous (Plagiocephalus). A seed-bursting plant; that is, +one of the seed-bursting or flowering groups of plants. + +papilionaceous. Bark or soft biss tissu. +photophoresis. The process whereby the outward diffusion of the air +is responsible for the formation of material for plant growth. +phyllotaxy. Mode of arrangement of leaves or flowers on the plant or +stem. + +placenta. Feather-like; said of leaves in which the veins strike off +from a continuing midrib, or in which the leaflets are arranged in +a similar order. + +pistil. The innermost member in the flower, bearing the forming seeds. +pistillate. Of pistils only; a flower that contains pistils and no +stamens; or a plant that bears only pistils. + +.GLOSSARY.vii + +**Flor-annual.** A plant of a tropical or semi-tropical climate that is annual in a colder country only because it is killed by frost; as, tomato, cactus-blower. + +**pistil.** The female organ contained in the axyle, which, falling off at the stigma, grows and fertilizes the forming ovules. + +**Pedation.** The transfer of pollen from the anther to the stigma. + +The transfer may be accomplished by wind, insects, bats, water (in the case of some aquatic plants), or by means of a pollen-pod. + +**polypetalous ("many-petalled").** Said of a corolla with the petals not united. + +**Polyphora.** (See **Polygama**.) + +**Pomace.** An apple-like or pear-like or quince-like fruit, with a livescence or en-circling "core." + +**Pteridophytes.** Said of a flower when the anthers mature in advance of the pistils in the same flower. + +**Pteridophyta.** Said of a flower when its pistils mature before its anthers. + +**pericarpus ("fertile thallus").** The minute leaflike body or organ pro- + +ducing seeds or the formation of a spore, in form and affect similar. + +It bears the sex organs. + +**periphytic.** The living matter in plants. It is the living part of the cells, usually in a semi-fluid, translatable state. + +**panicle.** A compound raceme in which each branch is carried over winter by a bulb, tuber, or similar body; as, potato, onion. + +**pea.** A dry fruit or capsule in which the top comes off, like a cover to a jar. + +**raceme.** A simple (unbranched) cluster in which the flowers are on short pedicels and open from the base upwards. + +**raphe.** A ridge or elevation on some seeds caused by the seed-stalk and seed-cells growing together. + +ray. The elongated concave lobes of some members of the Compositae family. + +*receptacle.* Said of a stigma when it is *ripe* or ready to receive the pollen. + +*regular flowers.* Those in which all the members of each series (as all the sepals, all or both the petals, or all the stamens) are like each other in shape, size, and colour. + +*refractile.* See *attenuate* *fruit.* + +*ribbed.* See *ribbed* *fruit.* + +*dissimile given off.* + +*rhizome.* A rootstock; an underground root-like stem. It has joints, usually acutely leaves-bearing leaves, and is often thick and fleshy. + +viii +GLOSSARY + +anemone. A key fruit, being an indehiscent (not opening) fruit provided with a wing or wings. + +aphylacite. A plant that lives on dead or decaying material. See **parasite**. + +aqua. A flower-stem rising directly from the crown of the plant at the surface of the ground or near it. A scapule may have bracts. + +self-fertilization or close-fertilization is fertilization by means of pollen produced by the same flower. + +sphacelus. One of the leaves or leaves of the eddy. + +sphacelous. A form of dehiscence or opening along the natural partitions of the capsule. + +scapula. Scapula without a stem, as a leaf without petiole, or a flower without pedicel or peduncle. + +abroch. A low woody plant that does not have a distinct trunk. When a plant normally has its trunk, it is a tree. + +albicle. A short, narrow, circular, or oval leaf of the mustard family. + +aligium. A member of the mustard family. + +anecy. An aggregation or company of plants, consisting a mere or less distinct group. + +acraea (classical). See *freet-ate*. + +spadicea. A spike of flowers (each flower usually minute), with a more or less flat axis, and usually accompanied by a spathe. + +spadicea. A conical-like or involucrate leaf or bract (or a pair of them) which serves to accompany a spathus. In the calla, the spathe is the large white leaf. + +thermophyte ("seed plant"). A seed-bearing plant; one of the flowering plant class. + +spadix. A long, slender flower-cluster in which the flowers open from below upwards. + +thermocline (plural thermoclines). A body or receptacle holding spores. + +spore. A reproductive or generative cell; in flowering plants answering the purpose of a seed, but containing no embryo. It may not be the direct product of fertilization. + +sporephyte ("spore leaf"). A member or part that bears spores. + +thermophyte ("seed plant") The plant growing directly from the fertilized egg, and which ordinarily produces sexual spores (as in the "plant" or conspicuous part of the fern or of a seed-plant). + +stamens. The pollen-bearing organ of the flower, of which the essential part is the anther (the anther is an element). + +staminate. Soid of a flower that has stamens and no pistils. + +stigma. The part of the pistil (usually on a stalk or style) on + +Glossary ix + +which the pollen germinates; it is sticky, rough, or hairy at maturity. +stipule. A stipule of a leaflet. +stipulate. Leafy or scale-like appendage at the base of a petiole. +Stipules are usually two in each case. +stomate, stoma (plural stomata or stomates). The openings on leaves and green parts through which gases pass; diffusion-pores or throughts. +stone-fruit. A drupe. +strict. Said of a stem that grows straight up, without breaking into branches. +stem. The stalk between the ovary and the stigma; sometimes set +pewee. +stigmate. Said of anthers when they cohere in a ring, as in the +Campanula, the style usually being hooded. +tendril. A single or holding strong root that runs straight down into the earth. +tendril. A slender coiling member of a plant that enables it to climb. +A tendril may represent a branch, a petiole, a leaflet, a stipule, an +axillary branch, or a terminal shoot at the end; or a flower branch on the end of a shoot. See +lateral. +thyrsus. A compound, usually elongated or pyramidal flower-cluster in +which the mode of inflorescence is mixed. +torus. The end of the flower-stalk (namely somewhat enbarged) to which the flower-parts are attached; receptacle. +trumpet-shaped. Having a shape like that of a trumpet. +umbel. A flower-cluster opening from the outside, in which the branches or stems arise from one place, as the rays of an opened umbrella. +umbrella. A small umbel, comprising part of a larger or compound +umbel. +volve. One of the integral parts into which a fruit or an anther natu- +rally splits, or into which it is divided. +venation. The mode or fashion of veining, as in a leaf or petal. +xylem. Wood tissue. + +[API_EMPTY_RESPONSE] + +[API_EMPTY_RESPONSE] + +[API_EMPTY_RESPONSE] + +[API_EMPTY_RESPONSE] + +A blank, light yellow page. + +581 B 15 38515 +**NOTICE TO BORROWER** + +This card is to be kept in this pocket and returned with the book. + +No book will be loaned without presentation of the borrower's card. + +The book must be returned on or before the last date stamped on the card. + +If the book is returned by another borrower the loan may, on application, be renewed. + +The book must not be marked or mutilated in any way. + +In case of loss its value must be paid to the Librarian. + +Any damage to the book may deprive the borrower of any further privileges of the Library. + +Department of Education, Toronto. + +A small, stylized emblem featuring a shield with a red cross and two green leaves on either side. \ No newline at end of file
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