[Illustration: Courtesy Journal of the International Garden Club] [Illustration: _The prickly pear (Opuntia chlorotica santarita) of the desert in the American Southwest._ (_This painting was kindly loaned by Dr. David Griffiths of the United States Department of Agriculture and reprinted here through the courtesy of the Journal of the International Garden Club, where it first appeared._)] POPULAR SCIENCE LIBRARY EDITOR-IN-CHIEF GARRETT P. SERVISS AUTHORS WILLIAM J. MILLER HIPPOLYTE GRUENER A. RUSSELL BOND D. W. HERING LOOMIS HAVEMEYER ERNEST G. MARTIN ARTHUR SELWYN-BROWN ROBERT CHENAULT GIVLER ERNEST INGERSOLL WILFRED MASON BARTON WILLIAM B. SCOTT ERNEST J. STREUBEL NORMAN TAYLOR DAVID TODD CHARLES FITZHUGH TALMAN ROBIN BEACH ARRANGED IN SIXTEEN VOLUMES WITH A HISTORY OF SCIENCE, GLOSSARIES AND A GENERAL INDEX _ILLUSTRATED_ [Illustration] VOLUME THIRTEEN P. F. COLLIER & SON COMPANY NEW YORK Copyright 1922 BY P. F. COLLIER & SON COMPANY MANUFACTURED IN U. S. A. BOTANY THE SCIENCE OF PLANT LIFE BY NORMAN TAYLOR CURATOR, BROOKLYN BOTANIC GARDEN [Illustration] P. F. COLLIER & SON COMPANY NEW YORK PREFACE This book is for those who want some general knowledge of the plant world, without necessarily caring for the technical details upon which such knowledge is based. If it leaves the reader with an impulse to follow the subject further than has been possible here, it will have more than fulfilled its mission.