Plant life and plant uses; an elementary textbook, a foundation for the study of agriculture, domestic science or college botany

Front matter

New York State College of Agriculture

Library nT

Cornell University

Preface

Tus book is for boys and girls who study about plants. It is a book about the fundamentals of plant life, and about the relations between plants and man more than it is a “textbook of botany.” Yet it presents, as fully as the author believes to be desirable in required courses, those large facts about plants which form the present basis of the science of botany. These facts also form, it is believed, a minimum of knowledge about plants to which every high school student is entitled. To present this minimum adequately, rather than lengthily to cover a maximum, has been the aim.

Appreciation. — The book seeks to give its reader a certain appreciation of plants and of the relationship of plant life to his own life. The study of “botany” may or may not yield such appreciation. Boys and girls by mere accumulation of “ organized knowledge about plants” may never come to that appreciation of plants as a part of life which is believed to be very desirable, and one of the proper ends of the study of plants in high schools.

Delimitations. — The book presents the large essentials of plant life. It emphasizes their significance to man. But it does not pile up specific illustrations and applications which may not illustrate or apply in what is common to the lives of high school students in general. The effort is to include what has proper place in the education of a// young people, and to exclude special information which properly has required place only in the education of some young people. Thus, as to agriculture, it is believed that such general study of plants as is presented herewith should precede the special study of that subject, but it is doubted

Vv vi PREFACE whether such study of plants as is required of all students should be a study primarily of agriculture. In so far as is possible, plant life is presented in this book in terms of its largest relations to human life, but the treatment has in view preparation for life in general, and not preparation for any particular kind of calling.

Forestry, Plant Breeding, Weeds, Plant Enemies and Diseases, Plant Culture, Decorative Plants, and Economic Bacteria are topics which are discussed where such discussion seems pertinent to the general theme, but special chapters are not devoted to these topics. Certainly such topics should form a part of the course, especially if it is a year course, but it is questionable whether special chapters on such topics should form a part of the basic text. Such topics, treated in separate chapters, seriously impair that unity of organization which should characterize a foundational text. Also they form that part of the course which the teacher needs to organize largely in terms of the locality. A treatment of the fundamentals of plant life may fit all cases, but any treatment of the topics given above will not fit all cases, and the misfits may do the cause of practical plant study more harm than good. Thus town children and parents have rebelled against plant studies which are purely agricultural. Finally, government and state bulletins of local application and works of reference have been found to be of much better service in the study of such topics than any brief miscellany of facts put together in “special chapters.”

Coherence. — The pupil's facts should hang together for him. In this sort of course he needs to see relationships. This outcome may hardly be expected when there is an overload of facts included for their own sake and at the expense of the course as a whole. Like plants themselves,

PREFACE vii courses dealing with plants are often in need of pruning in the interest of the fruit desired.

It is a pruned-back course which is presented herewith, even though the informal style of presentation may lead the reader sometimes to think it otherwise. Omissions have been weighed equally with inclusions. In the interest of a certain end in view, whatever seemed dispensable has been dispensed with. That certain end in view is a broad and a true conception of plants and of their principal relations to mankind. If our subject is to be a science, and not a mere mass of information, then such a conception is the first claim upon plant knowledge which we are called upon to satisfy, as well as the necessary foundation for additions of special knowledge. All that is herein included is meant to be contributory to that conception ; bricks, as it were, in that foundation.

Style. — The manner of the book has been determined by a desire to make what is important seem interesting to young readers. If the author has been successful in what he has attempted, the intellectual effort per page needed to comprehend the text will be considerably less than if the book had been written with the idea of a formal textbook in mind. The teacher, in making assignments, should take this matter into consideration.

Introduction. — The introduction aims at appreciation. It rests on the principle of Herbart that “the pupil must know from the beginning what is aimed at if he is to employ his whole energy in the effort of learning.” It is a frank attempt at motivation. It may be included or it may be omitted in the assignments. It falls into two parts. The first is devoted to appreciation of the subject matter to be studied; the second, to appreciation of the method of study to be used. The idea of this second part is to get viii PREFACE the student interested at the very outset in scientific method, and to lead him to see that this method may be of great value to him in life as well as in the laboratory. Trial of this introduction has indicated that more of interest and effort is aroused when such material is included than when it is omitted. Many teachers have been interviewed as to their opinion of such an introduction. It is evident that the idea meets with approval, whatever opinion may prove to be as to the manner in which it is carried out in this book. If the introduction is used as lessons, it should be used before laboratory work is begun.

Maintenance of Effort. — Just so far as is practicable, the familiar always precedes the unfamiliar in the sequence of topics. With a view to maintenance of effort as well as of znterest, the amount of “resistance” is gradually increased as the reader progresses. Thus the technical discussion of foods is postponed until Chapter IX, while the non-seed plants, and the “hidden” parts of seed plants, are discussed in the last two chapters. Yet these two chapters, if what comes before is well understood, need be no more difficult than the earlier chapters. Alternation of generations and the morphological nature of seeds are not topics intrinsically difficult. Only their unfamiliarity makes them seem difficult. The exclusion of these topics is warranted only by a teacher’s inability to present them clearly. Their inclusion is warranted by their necessity to even the most elementary conception of plant evolution, and by the need of them in any adequate conception of seed plants themselves.

Plan of Presentation. — The plan of presentation is, in a limited sense, spiral. Chapters I and II give a general view of a seed plant as a whole. Chapters III to VIII are devoted to an expanded treatment of what is briefly

PREFACE ix touched on or suggested in the first two chapters. In Chapters IX and X the plant kingdom is considered in the evolutionary sequence.

The Questions and Suggestions which follow the chapters are of two kinds. Some are designed merely to serve as an aid in the study of the text, while others suggest study and inquiry outside of the text. Of this latter kind there are more than any one student is expected to cover. Selection will be made of such as are most suitable to local conditions.

Technical terms have been used only as real need for them has been developed. Upon first occurrence they are printed in italics.

Attention is called to the classified tables of terms which immediately precede the Index. These are designed to serve the student in review, and to be a general guide to the relative values of the facts presented.

Acknowledgments. — The sources of this book lie in modern botanical literature in general, but the chief source has been the Coulter, Barnes, and Cowles ‘“ Textbook of Botany.” For spirit of treatment as well as for data, I am much in debt to Dr. Cowles’s part of that work, the part on ecology. That work is also the chief source of the non-original illustrations used herein. The illustrations which are original are all the work of Miss Anna Hamilton. For critical reading of the manuscript I am gratefully and especially indebted to my father, Dr. John M. Coulter, to Dr. Cowles, and to Dr. Crocker.

JOHN G. COULTER.

Bioomincton, ILL., July, 1913.

Introduction

PAGE

PLANTS AND OURSELVES . ‘ : : : : 3 ‘ 1 Section 1, Our dependence upon plants . ‘ , ‘: ‘ 1 Section 2. Our enjoyment of plants . 3 4 . 4 Section 3. Plants in spring : : . e . 5 - 10 Section 4. Plants and history . oe: 3 : : : 3 ae [ukd, Section 5. The improvement of crops. . F . 4 . » 1 THE STUDY OF PLANTS ‘ F ‘ ‘ a = a . 18 Section 6. Reasons for it j : ‘ F : : - . 18 Section 7. Ways of doing it . ‘ . ‘ ‘ F . 21 Section 8. Your first plant study j 3 : , ‘ » 24 Section g. Later studies . 3 ‘ ‘ ; ¢ : x | 29 Section 10. The notebook . : : é : é » 31 Section 11. The textbook . : ; . - . 34

Chapter One: The Plant A General External View

Section 12. Seed plants and other plants : 38 Section 13. Plant life and ours . : 38 Nutrition and reproduction . ‘ ‘ 40

Section 14, Nutrition . : " : 40 A. Food. é : - . : j : » 41

4. Digestion and assimilation. ; ‘ 42

C. Photosynthesis : ‘i i : » 4

D. Organs and functions. : : E A 44

&. Protection. ‘ ; : A ; 45

Section 15. Roots ‘ : & : . 45 Section 16. Stems. . ‘ ‘ : . 49 Uses of stems to man . - " : «192

Section 17, Leaves. i F a é . : » 93

Section 18.

Section 19.

Section 20.

Section 21.

Section 22.

Section 23.

Section 24.

Section 25.

Section 26.

Section 27.

Section 28, Section 29.

Section 30.

Section 31.

Section 32.

Section 33.

Section 34.

Reproduction .

Flowers

Fruits

Seeds

CHAPTER TWO: THE PLANT A GENERAL INTERNAL VIEW The inside of plants Cells and protoplasm Tissues

From root to leaf Inside the leaf

The working together of the stile aeduine .

CHAPTER THREE: NOT ALTOGETHER ABOUT PLANTS A break in the story Solution . ; Molecules

States of matter Elements and compounds Atoms : Compounds aid mixtures

Section 34 A. Soil

Section 35.

Section 36.

Section 37.

Section 38.

Section 39.

Section 4o.

Section 41.

A. Origin and icine af sai:

B. Soil and food .

C. Fertilizers and cultivation Osmosis . : Causes of continued entrance Forms of energy Evaporation Physics and Ghemaistey ad life

Life a procession of changes

CHAPTER FOUR: ROOTS Topics . ‘ ‘

Introductory as to roots .

71 72 77 78 84 86

123 124

Section 42.

Section 43.

Section 44.

Section 45.

Section 46.

Section 47.

Section 48.

Section 49.

Section 50.

Section 51.

Roots as to origin

a, Primary roots

ZB. Secondary roots

C. Branches of roots: Structure and growth of roots

A. Root curvature

&. Tropisms of roots .

C. Root-cap

D. Root-hairs

#, Cortex and stele

Duration of roots. Annuals, bienniale, ada pereuale , Contraction of roots CHAPTER FIVE: STEMS Introductory Aérial stems . . 4 ‘ f Z A

A. Erect stems

B. Prostrate stems

Cc. Climbing stems

D. Exceptional forms of stems Underground stems

A. Rhizomes

&. Tubers 3

Cc. Bulbs. 7 ‘

D. Corms

£. Stools The vernal habit é The structure and growth of stems Contrast with roots ; Epidermis, cortex, and stele .

Arrangement of the vascular bundles The cylindrical arrangement .

The scattered arrangement Cells of the bundles Rings in the wood. Age of trees .

The bark and things related to it. Lenticels . Grafting and budding Stems in the classification of seed silent

Sats ada

Section 52. Buds and branches A. Kinds of buds &. Overproduction of buds Section 53. Accumulation in stems A. Why not “storage”? 4. Substances accumulated Cc. Latex Section 53 A. Forestry A. Importance af: forests &. Aims of forestry C. Forestry outside of forests a CHAPTER SIX: LEAVES

Section 54. Introductory A. Use and beauty of reas B. Points already noted Section 55. External characteristics . ad. Venation B. Shape

Cc. Attachment and er

D. Leaf surfaces

£. Leaf size and foliage area Section 56. Functions

A. Transpiration

8. General relation of water to thé vlan

C. Respiration D. Photosynthesis

£. Summary as to gaseous exchanges

Section 57. Structure A. Epidermis 8. Stomates C. Mesophyll D. Veins Section 58. Protection

A. The shedding af jeans anil their siinasccmdl salons

B. Movements of leaves

C. The edgewise position - Section 59. Special forms of leaves

A. Needle-like leaves .

B. Leaves as insect traps.

XIV

Section 60.

Section 61.

Section 62.

Section 63.

Section 64.

Section 65.

Chapter Seven: Flowers

A. Pollination

C. Evolution of flowers

D. Flowers as sex organs General structure .

A. Essential and accessory parts

#. The outer parts

C. The inner parts

D. The receptacle Variations in structure Z The evolution of flower forms . The simplest flowers Kinds of perianths . Variations of the andrcecium . Variations of the gyncecium .

Variations in the number of parts . . Monocotyledons and dicotyledons Inflorescences

A, Advantages

&. Kinds More about pollination

A. The waste of pollen

&. Kinds of pollination C. The stigma D £.

Arse dsawa

. Wind-pollination . Insect-pollination .

Yucca and pronuba Fig and wasp Prevention of close- pollination Cleistogamy ‘ Hf. Which kind of pollination i is batler? ?

ae

CHAPTER EIGHT: FRUITS AND SEEDS Functions of fruits and seeds

Section 66. The nature of fruits

A. Aid in dispersal &B. Classification of fruits C. Dehiscent and indehiscent fruits

PAGE

325 328 328 330 330

D. Dry and fleshy fruits 4. Inflorescence fruits F. Self-planting fruits .

G. Seedless fruits Section 67. The nature of seeds The importance of seeds to madttind The importance of seeds to plants Protection of and by seeds . Vitality of seeds Structure of seeds Cotyledons and the divisions of cea pita : Seeds and foods . Germination of seeds Section 68. Agencies of seed dispersal A. Wind © B. Water C. Animals .

see

Chapter Nine: The Non-vascular Plants

Section 69. Introductory ‘ : Section 70, The four great divisions .

THALLOPHYTES :

Section 71. Algz : A. Unicellular ee £&. Colonial forms C. Many-celled fresh-water fine D. The groups of algze Section 72. Fungi : . : : Parasites and saprophytes Economic importance Bacteria .

True fungi Fungi and the soil .

Lichens .

Nh Sawa

BRYOPHYTES: Section 73. Liverworts A. Reproduction &. Alternation of generations C. Leafy liverworts

XV

PAGE

360 360

D. Green sporogonia

£&. Liverworts as ae : Section 74, Mosses

A. Renmaduction:

&. Increase of the sporoplinté

CHAPTER TEN: THE VASCULAR PLANTS Section 75. Introductory PTERIDOPHYTES

Section 76. Ferns

Section 77. Horsetails

Section 78. Club mosses Selaginella

SPERMATOPHYTES:

Section 79. Gymnosperms .

. Two kinds of cones

. Pollination

. The pollen tube

. The embryo

The seed

Why two sets of names? é : Pollen grains not exactly microspores .

. The female gametophyte

. Generations in the seed ‘i Summary of the life history of a gymnosperm ~ General summary .

Section 80. Angiosperms

. The greatest group ‘of lenis.

The flower .

The male parneneahute S

. The female gametophyte

Double fertilization

Plant breeding

ASN OBES ABA

~hsass

Key To INDEX AND GUIDE IN REVIEW .

INDEX .

PLANT LIFE AND PLANT USES

INTRODUCTION Part I[— PLANTS AND OURSELVES

1. Our Dependence upon Plants. — Plants are a part of life. Without them all life, our own included, would soon come to an end. Our lives depend upon their lives.

You are very much interested in life, but the importance of plants as a part of it may not have occurred to you. You know that food is one of the necessities of life, but you may not know that all food, directly or indirectly, comes from plants. You know that the country in summer is covered with plants. You know that their leaves hide the soil and make the hills and valleys green. But you may not know that green leaves are the food factories of the world.

When you eat an apple you are eating food that comes from a plant directly. When you eat an egg you are eating food that comes from plants indirectly. The hen which laid the egg lived on plants and on small animals which got their food from plants. All food comes thus from plants. Other living things can change foods from one kind to another, but only plants can change substances which are not food into substances which are food.

It is not for food alone that our lives depend upon the lives of plants. There are many other things which make them important to us. In this study you are to learn of I the important part which plants have in your own life, as well as of the nature of plant life itself.

Think of the many uses which we make of plants besides their use as food. From plants we get the principal material out of which homes are built, and it is plants that we use to beautify the grounds around our homes. When a man is able to make the sort of home he wants, he is sure to surround it with grass and trees, with flowers and shrubs. They seem a necessary part of the sort of home we all want. Think, too, of the use of plants for clothing. Cotton and linen are both made from materials taken from plants. Wool and silk come from animals which live on plants.

Food is the first need of man, and this need could not be supplied at all except for plants. Shelter and clothing come next in order of our needs, and for these too we depend very largely upon plants. Houses are for shelter, but they would be poor shelter in winter if they were not heated. Coal, wood, and gas are the substances principally used in producing heat, and all of these are derived from plants. Coal is composed of the transformed bodies of plants which lived many thousands of years ago, and gas is derived from coal. Even when we use electricity we are usually depending indirectly upon plants, for the power-houses which generate the electricity use steam engines, and coal is used to generate the steam. The steam engines, in turn, run the machines which generate the electricity. Think of all the factories, and locomotive engines, and steamships which also use coal. Evidently one of the principal uses of plants to man is that they provide him, or have provided him, with fuel. Gasoline has come to be one of the important kinds of fuel, especially in connection with automobiles. It is derived from petroleum, and petroleum, like

PLANTS AND OURSELVES 3 coal, was formed chiefly from the dead bodies of plants which were buried deep under the earth thousands of years ago. Lubricating oils are also derived from petroleum, while some oils, like cottonseed and linseed and castor oil, are derived from plants directly.

Wood is principally used in the building of houses and furniture, but there are other important uses of it. Think, for example, of the great quantities needed for telegraph and telephone poles, for railroad ties, and for fence posts.

Sometimes medicine is needed, and this need also is principally supplied by plants. Most of the drugs of which medicines are made are derived from plants. Rubber and gutta-percha, paper and perfumes, and many other much used substances are also derived from plants.

Each day you discover things which are new to you; things which make life seem to you more interesting and important. Just now you are to discover that knowledge of plant life will make your own life more interesting and more important. You are anxious to find out what you must know and what you must do in order to make your own life a success. The more you understand about life in general, the more likely you are to judge wisely for your own life in particular. To understand plant life and its relationships to human life will help you to understand your own life and its relations to the great world of which it is a part. You will learn that plants, besides furnishing food which makes life possible, may also furnish thoughts and feelings which make life pleasant; besides furnishing what is necessary to the development of our bodies, they may also furnish something needed for the development of our minds.

Plants are partners in life with us. They lived in the world before men lived in it, and they made the world habitable for men. The laws of life which control them are the laws of life which control us. To understand our own lives we must understand their lives. To understand their lives is to improve our own.

2. Our Enjoyment of Plants. — We enjoy the country chiefly because of the plants which cover it. We enjoy spring chiefly because then the grass turns green, flowers begin to bloom, leaves come out on the trees, and young plants grow up in the gardens. We may find it hard to explain this pleasure that we get from plants, but we feel it none the less. Something in us seems to respond to them. In fine weather we are glad to get out of the city, to go for a holiday into the country, to lie on the grass in the shade of trees, to look at what is green and growing.

The surface of the land is hidden by plants. They form the natural covering of the soil. Suppose you were up in an airship on a summer day. Green would be the color of the earth beneath you, the green of plants. The roads would make a few white lines across the green, and here and there you would see a house or catch a glimpse of a town. But nearly everywhere the earth’s surface would be green, — green with the millions of plants which grow upon it. Of animal life hardly any evidence at all would be visible.

Suppose it was a July day and you were looking down upon farm lands in the Mississippi Valley. Corn fields would be below you, miles on miles of them, deep green and growing, shining in the sun. Here and there you would see fields of wheat and oats, pale green or turning yellow, through with their growth and ready for the harvest. In some fields you

GOOMNSONN ONY GOAMmBIOWN (©)

would see men at work, the grain already piled in shocks. On hills and near streams you would see cattle grazing in the pastures, gathering their food from plants.

That great view of fertile country would delight you. Perhaps it would set you thinking. You might think of the miracle of nature by which this huge harvest has come from tiny seeds. You might think of the thousands of acres needed to yield food for one small city. You might think how small man isin the midst of the millions of plants which sustain him. You might think of the soil, that wonderful and complex layer which covers the rocks and holds, firmly and nourishingly within itself, the roots of plants; it is of the soil we think when we say ‘‘ Mother Earth,” for it is the soil which permits Earth to be “mother” of us all, plants and animals alike. As you looked down upon the great green carpet of plants below, you might remember that your own life depends upon this green life of plants, and perhaps you would feel grateful. At least you would enjoy its beauty, and might wish to know more about it.

Or suppose you were on a ship coming near to the steep shore of some tropical island. There vou would see no sign of men, but high above you would stretch hill and mountain sides, covered with the deep green of tropical forests, only the bare white trunk of a tree showing here and there. All the land would be hidden, the year round it is hidden, under this heavy mantle of plant growth. Trees you would see everywhere, trees even growing out to sea, as is a habit of some trees in the tropics. Coming nearer, you might see little houses along the shore, but all the work of men would be a trifle compared with the mass of vegetation surrounding it. And so wherever you go in

WY s the world, even to the very edge of the arctic circles, you will find plants in the growing season covering the earth with green, making it beautiful and fruitful, making it habitable for man.

Evidently plant life is one of the big things in the world in which you live. It is so big a thing and so important that you need to know about it. ‘You need to know about it whatever your business is going to be. Even though you are not going to be a farmer, or a florist, or a forester, or in any other way make your living directly out of knowledge of plants, none the less it will pay you to have such knowledge. It will pay you to be able thereby better to appreciate the work of the farmer, who works for us all. Though knowledge of plants may not pay you in money, it will pay you in something else which is just as important as money. Money helps us enjoy life. Knowledge of plants may also help us enjoy life, and even more certainly than money does.

Every boy who likes to fish or swim or tramp throughthe woods is a lover of nature. Every girl who likes to gather flowers or watch the sunset is a lover of nature. All of us, whether we call it that or not, have some love of nature. It seems to be born in us. The pleasure that we take in plants is a part of it, a very considerable part of it. Nothing will more certainly add to our enjoyment of life than cultivation of this love of nature, and one way to cultivate it is to learn about nature. The more you know about nature (of which plants form such an important part) the more you care for the country. Knowledge of plants and animals makes it a different place for you from what it was before. With your eyes opened by knowledge, you can enjoy the country more than most people enjoy

PLANTS AND OURSELVES 9 the city. To those who are interested in nature and understand her ways, life in the country is the most agreeable of all kinds of life. The farm boy who learns the ways of plants and animals finds more to interest him on the farm than he does anywhere else.

So, through knowledge of plants, something may be gained which makes the world, wherever we go, a far more interesting place than it was before. We gain something that gives every acre of ground and every plant growing on it a new meaning for us. We gain something that makes us enjoy finding out the names and habits of all the plants we meet; we wish to become personally acquainted with them and to watch their changes through the seasons. We gain something that makes us see in a grove of trees or in a field of corn things that we did not see before — things that change the trees and the corn to us; we see them with new eyes; their growth and their behavior become matters of the greatest interest; we know that they have a history just as we have a history and that as we keep changing so they too keep changing. This something that we gain may be called appreciation of nature, and those who possess it are very fortunate, for there is nothing in the world that is more certain to make their lives enjoyable. They can find pleasure in watching even a dusty patch of weeds, while woods and fields have for them a meaning like fine music.

You yourself in your study of nature in school can begin to get this thing which we have called the appreciation of nature, and the sooner you get it the more it will be worth to you. It is one of the finest things in life, and the study of plants, if you are truly interested in them, can lead you straight to it.

ake) INTRODUCTION

3. Plants in Spring. —It is in spring that we wonder most about plants. Whether you go into fields and woods or stay in town, it is the same. You see things growing. You watch the trees and shrubs turn green. You see green things sprouting from the cold and seemingly lifeless ground. Sometimes you seem almost to feel things growing.

Who can see, day by day, this fresh color coming back into the trees and over the ground, and not find pleasure init? Who can find the first violets, or see the first green coming among willows along brooksides, and feel no thrill?