AN INTRODUCTION TO STRUCTURAL BOTANY PART I FLOWERING PLANTS BY DUKINFIELD HENRY SCOTT M. A., LL. D., P. SC, F. B. 8., F. L. S., F. Q. S. LATELY HONORARY KBKlKR OP TUB JODRBLL LABORATORY, ROYAL HOTANIO OARDBNB, KRW AUTHOR OF STUDIES IK FOSSIL BOTANY AND THK KVOLUT1ON OF PLANTS WITH 117 FIGURES IN TUE TEXT AND A GLOSSARY NINTH EDITION A. C. BLACK, LTD. 4, 5 6 SOHO SQUARE, LONDON, W. 1917 All RigUs Reserved BY THE SAME AUTHOR. FLOWERLESS PLANTS. Uniform with this Volume, Sixth Edition, with 120 Illustrations. STUDIES IN FOSSIL BOTANY. Second Edition. Largo Crown 8vo, cloth. With 213 Illustrations. Price 10s. 6d. net. Or in Two Volumes. Vol. I. 6s. net. Vol. II. f s. net. For Press Notices of both the above, see end of book. FIRST EDITION, published April 1894 SECOND EDITION, November 1895 THIRD EDITION, April 1896 FOURTH EDITION, June 1897 FIFTH EDITION, June 1899 SIXTH EDITION, February 1902 Reprinted January 1906 SKVBSTH EDITION, January 1909 EIGHTH EDITION, November 1912 NINTH EDITION, April 1917. NOTE TO THE NINTH EDITION IN this edition several emendations of a minor character have been made, chiefly at the suggestion of a correspondent. A Glossary of the botanical terms used in the volume has been added. In preparing this I have frequently had occasion to consult Dr. Daydon Jacksons well-known Glossary of Botanic Terms and the Glossary to Kemer and Olivers Natural History of Plants. D. H. SCOTT. February 1, 1917. NOTE TO THE EIGHTH EDITION IN this issue the principal change is in the account of the transition from stem to root in the Wallflower pp. 79-81. This has been thoroughly revised in accordance with the unpublished observations of Mr. A. G. Tansley and Miss E. N. Thomas. Iam much indebted to Miss Thomas for her help in this matter, and especially for the new Figure 31, which she has kindly drawn for me from one of her sections of the transitional region. D. H. SCOTT. October 18, 1912. PREFACE TO THE FIRST EDITION THIS book is intended as a first guide to the study oi the structure of plants. Botany is now taught in schools of all kinds, and wherever Botany is taught it has become customary to expect some knowledge of the construction of plants, and of the function of their organs. All that I have aimed at in this book is to secure that such knowledge, when first acquired, shall be correct as far as it goes. My purpose has been to write an Introduction to Structural Botany, not a manual of Botany in general. It is absolutely necessary that schoolboys and girls, if they are to learn this science at all, should also gain a knowledge of plants in the field. For this part of the work a guide is necessary, and some such book as Professor Olivers Lessons in Elementary Botany is indispensabla The type-system has been adopted, as far as practicable, because it seems better to gain as thorough a knowledge as possible of a few plants, rather than to acquire mere scraps of information about a larger number. The types have been specially in vestigated for the purpose of thiB book, and many of vii viii PREFACE the figures are original. 1 For the rest, the authority ia cited. An effort has been made to point out those structural characters which are of wide importance, as distinguished from those which are peculiar to the type, or its nearer allies. The subject-matter is not always easy, and some parts of the book will riot be followed without close attention. There isreally no reason why Natural Science should be regarded in schools as a specially easy suljj t. If Science is to be taken seriously, it rather seems desirable that those who study it should have to use their brains as much as in learning Euclid, Algebra, or Grammar. If any real knowledge of the subject is to be gained, practical work is essential. It is expected that the teacher should have sufficient training to be able to demonstrate to his class most of the structural features described in the book...