Chapter I: Preface

In preparing the present volume, the aim of the writer has been to meet all the college entrance requirements and at the same time to bring the study of botany into closer touch with the practical business of life by stressing its relations with agriculture, economics, and, in certain of its aspects, with sanitation. While technical language has been avoided so far as the requirements of scientific accuracy will permit, the student is not encouraged to shirk the use of necessary botanical terms, out of a mere superstitious fear of words because they happen to be a little new or unfamiliar. Such a practice not only leads to careless and inaccurate modes of expression, but tends to foster a slovenly habit of mind, and in the long run causes the waste of more time and labor in the search after roundabout, and often misleading, substitutes, than it would require to master the proper use of a few new words and phrases.

In the choice of materials for experiment and illustration, the endeavor has been to call for such only as are familiar and easily obtained. The specimens for flower dissection have been selected mainly from common cultivated kinds, because their wide distribution makes them easy to obtain everywhere, while in cities and large towns they are practically the only specimens available. Another important consideration has been the desire to spare our native wild flowers, or at least not to hasten the extinction with which they are threatened by the ravages of Sunday excursionists and summer tourists, to whose unthinking, but none the less destructive, incursions, the automobile has laid open the most secret haunts of nature. The influence of the public school teacher, and more especially the teacher of botany, is the most potent factor from which we can hope for aid in putting a stop to the relentless persecution that has practically exterminated many of our choicest wild plants and is fast reducing the civilized world to a depressing monotony of weediness and artificiality. Except for purely systematic and anatomical work, flowers can be studied to better purpose in their living, active state than as dead subjects for dissection; and the best way to show our interest in them, or to get the most rational enjoyment out of them, is not, as a general thing, to cut their heads off and throw them away to wither and die by the roadside. The teacher, by instilling into the minds of the rising generation a reverence for plant life, may do a great deal to aid in the conservation of one of our chief national assets for the gratification of the higher esthetic instincts. The fruits and flowers of cultivation do not stand in the same need of protection, since they are produced solely with a view to the use and pleasure of man, and their propagation is provided for to meet all his demands.

To avoid too frequent interruptions of the subject matter, the experiments are grouped together at the beginning or end of the sections to which they belong, according as they are intended to explain what is coming, or to illustrate what has gone before. A few exceptions are made in cases where the experiment is such an integral part of the subject that it would be meaningless if separated from the context. Under no circumstances should those capable of being performed in the schoolroom be omitted, as much of the information which the book is intended to give is conveyed by their means. For this reason, and also because the aim of the book is to present the science from a practical rather than from an academic point of view, the experiments outlined are for the most part of a simple, practical nature, such as can be performed by the pupils themselves with a moderate expenditure of ingenuity and money. The experience of the writer has been that for the average boy or girl who wishes to get a good general knowledge of the subject, but does not propose to become a specialist in botany, the best results are often obtained by the use of the simplest and most familiar appliances, as in this way attention is not distracted from the experiment itself to the unfamiliar apparatus for making it. In saying this, it is not meant to underrate the value of a complete laboratory equipment, but merely to emphasize the fact that the lack of it, while a disadvantage, need not be an insuperable bar to the successful teaching of botany. It is, of course, taken for granted that in schools provided with a suitable laboratory outfit, teachers will be prepared to supplement or to replace the exercises here outlined with such others as in their judgment the subject may demand. There are as many ideals in teaching as there are teachers, and the most that a textbook can do is to present a working model which every teacher is free to modify in accordance with his or her own method.

The writer takes pleasure in acknowledging here the many obligations due to Professor Francis E. Lloyd, of the Botanical Department of the Alabama Polytechnic Institute, at Auburn, Ala., for his valuable aid in the revision of the manuscript, for the highly interesting series of illustrations relating to phototropic movements, and for advice and information on points demanding expert knowledge which have contributed very materially to whatever merit this volume may possess.

Other members of the Auburn faculty to whom the author feels especially indebted are Mr. C. S. Ridgeway, assistant in the Botanical Department, Professor J. E. Duggar, of the Agricultural Department, and Dr. B. B. Ross and Professor C. W. Williamson of the Department of Chemistry. Acknowledgments are due also to Professor George Wood of the Boys’ High School, Brooklyn, for suggestions which have been of great assistance in the preparation of this work; to Professor W. R. Dodson, of the University of Louisiana, for illustrative material furnished, and to Professor William Trelease for the loan of original material used in reproducing the beautiful cuts from the Reports of the Missouri Botanical Garden, credit for which is given in the proper place.

For original photographs and drawings by the author, and familiar selections from well-known works, which can be generally recognized, it has not been thought necessary to give special credit.

E. F. ANDREWS.

AUBURN, ALABAMA.

FULL-PAGE ILLUSTRATIONS

PLATE PAGE

1. A GROVE OF LIVE OAKS NEAR SAVANNAH, GEORGIA _Frontispiece_

2. CARRYING WATER OVER THE MISSISSIPPI LEVEE BY SIPHON TO
IRRIGATE RICE FIELDS 8

3. AËRIAL ROOTS OF A MEXICAN STRANGLING FIG 73

4. A FOREST OF BAMBOO 99

5. A GROUP OF CONIFERS 108

6. A WHITE OAK, SHOWING THE GREAT SPREAD OF BRANCHES 117

7. A TIMBER TREE SPOILED BY STANDING TOO MUCH ALONE 125

8. AN AMERICAN ELM, ILLUSTRATING DELIQUESCENT GROWTH 130

9. VEGETATION OF A MOIST, SHADY RAVINE 151

10. A MOSAIC OF MOONSEED LEAVES 179

11. HYBRID BETWEEN A RED AND A WHITE CARNATION 227

12. GOOSEBERRIES, SHOWING IMPROVEMENT BY SELECTION 251

13. THE EFFECTS OF IRRIGATION 272

14. A XEROPHYTE FORMATION OF YUCCAS AND SWITCH PLANTS 282

15. A GIANT TULIP TREE OF THE SOUTH ATLANTIC FOREST REGION 293

CONTENTS

CHAPTER I. THE SEED PAGE

I. THE STORAGE OF FOOD IN SEEDS 1

II. SOME PHYSIOLOGICAL PROPERTIES OF SEEDS 10

III. TYPES OF SEEDS 12

IV. SEED DISPERSAL 21

FIELD WORK 28

CHAPTER II. GERMINATION AND GROWTH

I. PROCESSES ACCOMPANYING GERMINATION 29

II. CONDITIONS OF GERMINATION 33

III. DEVELOPMENT OF THE SEEDLING 40

IV. GROWTH 47

FIELD WORK 52

CHAPTER III. THE ROOT

I. OSMOSIS AND THE ACTION OF THE CELL 53

II. MINERAL NUTRIMENTS ABSORBED BY PLANTS 58

III. STRUCTURE OF THE ROOT 61

IV. THE WORK OF ROOTS 65

V. DIFFERENT FORMS OF ROOTS 72

FIELD WORK 80

CHAPTER IV. THE STEM

I. FORMS AND GROWTH OF STEMS 81

II. MODIFICATIONS OF THE STEM 88

III. STEM STRUCTURE

A. MONOCOTYLS 96

B. HERBACEOUS DICOTYLS 102

C. WOODY STEMMED DICOTYLS 107

IV. THE WORK OF STEMS 112

V. WOOD STRUCTURE IN ITS RELATION TO INDUSTRIAL USES 118

VI. FORESTRY 124

FIELD WORK 128

CHAPTER V. BUDS AND BRANCHES

I. MODES OF BRANCHING 131

II. BUDS 138

III. THE BRANCHING OF FLOWER STEMS 141

FIELD WORK 145

CHAPTER VI. THE LEAF

I. THE TYPICAL LEAF AND ITS PARTS 147

II. THE VEINING AND LOBING OF LEAVES 154

III. TRANSPIRATION 160

IV. ANATOMY OF THE LEAF 164

V. FOOD MAKING 168

VI. THE LEAF AN ORGAN OF RESPIRATION 174

VII. THE ADJUSTMENT OF LEAVES TO EXTERNAL RELATIONS 177

VIII. MODIFIED LEAVES 189

FIELD WORK 194

CHAPTER VII. THE FLOWER

I. DISSECTION OF TYPES WITH SUPERIOR OVARY 196

II. DISSECTION OF TYPES WITH INFERIOR OVARY 204

III. STUDY OF A COMPOSITE FLOWER 210

IV. SPECIALIZED FLOWERS 214

V. FUNCTION AND WORK OF THE FLOWER 219

VI. HYBRIDIZATION 223

VII. PLANT BREEDING 230

VIII. ECOLOGY OF THE FLOWER

A. THE PREVENTION OF SELF-POLLINATION 235

B. WIND POLLINATION 239

C. INSECT POLLINATION 241

D. PROTECTIVE ADAPTATION 245

FIELD WORK 249

CHAPTER VIII. FRUITS

I. HORTICULTURAL AND BOTANICAL FRUITS 250

II. FLESHY FRUITS 255

III. DRY FRUITS 260

IV. ACCESSORY, AGGREGATE, AND MULTIPLE FRUITS 265

FIELD WORK 269

CHAPTER IX. THE RESPONSE OF THE PLANT TO
ITS SURROUNDINGS

I. ECOLOGICAL FACTORS 271

II. PLANT ASSOCIATIONS 277

III. ZONES OF VEGETATION 288

FIELD WORK 294