The botany of crop plants; a text and reference book

Preface

This book has grown out of a course of instruction extending over a number of successive years. Most of the material presented here, except Part I, has been used in mimeographed form in college freshmen classes, not only as a text from which to make assignments, but also as a guide and reference in the laboratory. The issuance of the book has been stimulated in part by the expressed need of a number of schools for a text and reference book which will give the student a knowledge of the botany of common orchard, garden and field crops, and it is the author’s wish that the material brought together from many sources and organized in the present form will meet this need, at least in a measure.

It has seemed advisable to include chapters (Part I) which may be needed in some instances to refresh the student’s knowledge of certain fundamentals, or prepare him for that which follows in Part II. But in many schools Part II will be preceded by a general course which aims to give the student a survey of the plant kingdom and an acquaintance with the large outstanding facts and principles of botany, and in this case Part I will be omitted. - The subject matter of Part II is sufficient for a course of one-half year involving one recitation and two laboratory (5) periods per week.

In the preparation of the book, the writer has had in mind non-agricultural as well‘as agricaltural schools, for it cannot escape notice that there is a growing tendency, wherever botany is taught, to tie it up more closely with economic interests and to draw more and more upon economic plants in citing examples and in choosing objects of study in the laboratory.

vi PREFACE

The bibliographies are obviously incomplete. Most of the titles were made use of by the writer in the preparation of the manuscript, and to the authors of these he is under obligation. Bailey’s Cyclopedia of Horticulture has been indispensable and has been called into use frequently. The writer has also called upon the publications of the United States Department of Agriculture and of the various Experiment Stations. A number of the ‘‘keys” are original, many are adapted, and a few are taken verbatim. A majority of the illustrations are original. It is believed that ~ the direct method adopted herein of labeling drawings will appeal to both students and teachers.

Almost all original illustrations, and also those copied or adapted are the work of Mr. N. Lee Foster. The writer is especially indebted to him, not only for the delineation, but for his helpful interest and valued codperation throughout. Professor D. W. Frear, formeily Associate Professor of Agronomy at the Colorado Agricultural College, now of the North Dakota Experiment Station, is to be given credit for organizing and writing up portions of Chapters IX, XVII, XXX and XXXVIII. The text was planned and outlined by Professor Frear and the undersigned as joint authors, but unavoidable exigencies made it impossible for him to continue his connection .as author. The entire manuscript was painstakingly read by Louise Falk Robbins, and her suggestions have added greatly to the accuracy in many places.

W. W. Rossins.

CoLorADO AGRICULTURAL COLLEGE.

PART |

Principal Parts of the Seed Plant Body—Size and Form of the ‘Staal nani Bora hi Aaa oe eae Oia SOE Sees pra

CHAPTER II.—FuNDAMENTAL INTERNAL STRUCTURE OF PLANT Bopvy

Organs and Tissues—The Plant Cell—The Cell as a Unit of Structure—The Cell as a Unit of Plant Activity—The Structure of the Plant Cell—The Cell Wall—Plastids—Nucleus— | SFU SETE) SST alah AIR ig hl ee Sec a ll aah a a ed I es CHAPTER IITI.—Roots.

Development of Root Systems—The Work of Roots—Effect of Environment upon Character of Root System—General Characteristics of Roots—Classification of Roots Based upon Their Medium of Growth—Structure of Roots—Root Hairs, the Absorbing Organs of a Plant—Root-hair Zone—Structure of a Root Hair—Effect of External Factors upon Development of Root Hairs—Length of Life of Roots.............. CHAPTER IV.—StTems.

Development of Shoot System—Buds—Classification of Buds—Bud Variation—General Characteristics of Stems— How Does a Stem Grow in Length—Classification of Stems Based upon Their Medium of Growth—‘‘ Modified’? Stems— Structure of Stems—The Young Dicot Stem—Dicot Vascular Bundle—Growth in Thickness of Dicot Stem— Monocot Stems—Annual Rings—Bark—The Work of Stems.......... CHAPTER V.—LEavEs.

Development of Leaves—Parts of Leaf—Kinds of Leaves— Structure of Leaves—The Work of Foliage Leaves......... CHAPTER VI.—FLowErs.

Parts of Representative Flower—Development of the Flower —Stamens—Mature Pollen Grain—Pistil—Ovule—Pollination—Fertilization—Placentation—Symmetry of Flower— Relative Positions of Flower Parts—Union of Flower Parts— Incomplete Flowers—Inflorescence..........0....00 5.0.00 CHAPTER VII.—Fruits, SEED, AND SEEDLINGS. Development of the Seed—Development of the Fruit—Fruit and Seed Distinguished—Kinds of Fruits—Germination of SOE SES DURE SEE NOR a by Sa i ae ie Re A He

LO-2E

22-41

42-47

48-56

Vili

CHAPTER VIII.—TueE CLassiricaTION AND NAMING OF PLANTS.

Reproductive versus Vegetative Organs in Classification— Groups of Plants—The Plant Kingdom—Plant Nomenclature —Scientific Name—Scientific Name versus Common Name— General References: —.2 82. acest we rae se tere ee