FROM THE AUTHOR'S PREFACE TO

THE ENGLISH EDITION.

"THE present volume has been prepared in accordance with a desire expressed for some years past by many old pupils and others, to have a guide which . . . might serve as an introduction to larger and more comprehensive works. The author has therefore endeavored to condense within a moderate compass all that is essential as a foundation for future study; . . . and his experience for more than thirty years as a professor of botany has shown him the necessity of explaining every detail in simple language, and of arranging the subjects in such a manner as to facilitate their systematic study. . . . Great pains have been taken to bring the different subjects treated of down to the present state of science; and much care has been exercised in condensing the numerous details in each department, and in arranging them for systematic study."

June, 1883.

PREFACE TO THE AMERICAN

EDITION.

THE present volume is designed to give such an elementary account of structural and physiological botany, or of the inner and minute mechanism and activities of plants, as is now recognized to be needful in general education.

In the Introduction to her "Descriptive Botany," published last year, after explaining and enforcing the reasons for an early beginning of the study of plant-forms, and for steadily pursuing it by the method of direct observation, the author concludes with the following statement: "While the portion of botany to which this volume is devoted can not be learned from books, there is another part of this science that may be more successfully pursued by ordinary school methods of instruction. This is physiological botany. By means of diagrams and the explanations of the text, the scholar is enabled to perceive how and of what the parts of plants are built up, and what functions they perform in its history as a living being. A valuable manual on this branch of botany, by an eminent authority, will shortly appear in this series, which will complete the exposition of the science here begun."

PREFACE TO THE AMERICAN EDITION. vii

That promise is now .fulfilled. The author of the work, Dr. Robert Bentley, is an eminent English botanist, who has had more than thirty years of practical experience as a teacher, and whose various text-books hold a first place in his own country. These works are mostly devoted to medical botany, but the present is a general treatise prepared for a less advanced class of students, and is a model of clear, concise, and accurate statement, giving a complete popular view of the minute structures, the functions, and the development of the various organs of plants.

The publishers of this work purchased the electrotypes of the wood-cuts of Professor Bentley's book, together with the right to edit and publish the volume. It was too large for popular use, and the editing has consisted mainly in lessening its size. In making the changes that have been necessary to reduce the volume to the limits desired by American classes, the author's text has been but little disturbed. The alterations have consisted in omissions of certain parts which are already given in full in the "Descriptive Botany," where they properly belong in the present course of botanical study.

While in descriptive botany the properties and relations of the organs of plants must be learned by direct observation, the inner processes of plant-life are clearly far less open to inspection, and we have to rely more upon illustrations and explanations. Physiological botany is therefore better adapted for school-room exercises. But, while it is recognized that a valuable knowledge of physiological botany may be gained from books, yet it is desirable that,

viii PREFACE TO THE AMERICAN EDITION.

as far as possible, facilities for observation and experimental study should be made use of. Every class should have a microscope, and there are various simple instruments that will be found serviceable in practical study. But this can not be carried far without special guidance, and there are several excellent manuals, any of which might be consulted. But the "Handbook of Plant Dissection," by the editors of the "Botanical Gazette," just published by Holt & Co., may be specially commended as an admirable guide both in furnishing a botanical laboratory and in conducting a course of inquiry into minute vegetable anatomy. E. A. Y.

May, 1886.