PREFACE 



This book is an attempt to give an account of the way 

 in which the flowering plant lives, especially in relation 

 to its environment. This, it might be said, is the aim 

 of ecology ; but ecology approaches the plant as a member 

 of a community, while biology, as it is understood here, 

 is interested rather in the plant as an individual. In its 

 methods biology has, during the last generation, become 

 more and more experimental ; it builds on a foundation 

 of physiology. A certain amount of pure physiology 

 must therefore be introduced. The difficulty of giving 

 enough to make the foundation sound, and yet not so 

 much as to obscure the picture, has been fully reahsed, 

 though perhaps not overcome. 



The great majority of the drawings in the text are 

 the work of Miss A. M. Davidson ; about one-third 

 are original, and these bear her initials, the remainder 

 are copied, sometimes with modifications, from various 

 sources which are acknowledged in the underlines. I am 

 indebted to Professor J. E, Weaver for permission to 

 reproduce Figs, i, 2, 4, and 5 from his Ecological Relations 

 of Roots. Fig. 50 is taken from Miss E. Kirkwood's 

 Plant and Flower Forms. The photographs are original, 

 and for help in their preparation I am indebted to Mr. 

 J. G. Taylor. 



I wish to express my thanks to Professor J. Arthur 

 Thomson, the general editor of this Series, for his kind 

 and stimulating criticism ; to Professor W. G. Craib for 



