PREFACE 



narrowly circumscribed of necessity, one should perhaps be thankful that in the midst 

 of the difficulties of this atomic age any progress has been made at all. 



It would be invidious, in a work which owes such a heavy debt to others, to select 

 many names for special mention. An exception must, however, be made for Pro- 

 fessor W. H. Lang, without whom the work would not have been done at all. And of 

 the many contributors who are not my colleagues, I must record a special debt to 

 Dr R. L. Praeger of Dublin, Mr F. Ballard of Kew, Mr A. H. G. Alston of the British 

 Museum, and Dr B. T. Cromwell of Hull. For personal assistance I am specially indebted 

 to Professor Lang's former research assistant, Mr Ashby, for help over the many years 

 I spent in Manchester, and, more recently, to Mr B. Clarke for similar assistance in 

 Leeds. Finally, I am indebted to the Oxford University Press, for permission to 

 reproduce various figures from my own papers in the Annals of Botany and the Journal of 

 Experimental Botany, to the Royal Society for similar permission regarding papers in 

 their Proceedings and Transactions, to Professor R. Nordhagen of Oslo and Professor 

 P. Martens of Louvain for permission to use Figs. 49 and 142 respectively, and to various 

 friends and colleagues for the originals of photographs which have been reproduced 

 as figures, notably to Professor Lang for Figs. 8a, 12 and 143, to Dr H. F. Dovaston 

 for Fig. 98 and to Mr Ashby for many of the natural-sized and low-power photo- 

 graphs throughout the book. 



L MANTON 

 Leeds 

 December 1949 



