PREFACE TO FIRST EDITION xi 



restricted senses, but a general term for the water- 

 conducting elements is indispensable, and De Bary's 

 usage answers every purpose. 



As in my Introduction to Structural Botany, the form 

 megaspore is used throughout, in preference to macrospore, 

 on the ground that the former term is more correct, 

 and less liable to verbal confusion with microspore. 



More than a third of the illustrations are new, and 

 of these the majority (over forty in number) were 

 drawn for me by Mr. Gwilliam, as indicated by his 

 initials, G. T. G. In addition, a considerable number 

 of the borrowed figures were redrawn by the same 

 artist, to whose skill the book is much indebted. 



Of the figures which are not new, a great many are 

 taken from memoirs by the late Dr. W. C. Williamson, 

 F.R.S., by myself, or by both of us, jointly. The 

 source of all figures borrowed from other authors is of 

 course acknowledged. I have to thank the Royal 

 Society for permission to reproduce a large number of 

 figures from the Philosophical Transactions, and the 

 Linnean Society for a similar permission in the case of 

 that Society's publications. 



Mr. W. Carruthers, F.R.S., has kindly allowed me to 

 make use of some illustrations from his well-known 

 memoir on fossil Cycadean stems. 



The restoration of Lyginodendron Oldhamium, form- 

 ing the frontispiece, is the work of Mr. J. Allen, who 

 has carried out a difficult task with much ability. 



For various photographic illustrations I am indebted 

 to Dr. E. C. Bousfield, and to my colleague, Mr. L. A. 

 Boodle. 



Wherever possible, I have given the number of the 



