PREFACE TO THIRD EDITION i x 



finally, I have added in Chapter XXXVI. a condensed statement 

 " The Relation of Size and Form in Plants ". Some may be surpri 

 to find that subject introduced into a current Text-book ; holding 

 this to be premature until opinion is more settled than it is al pn 

 Whether or not adherence be given to the views expressed in the Chap- 

 ter, it seems desirable to raise the topic, (i) as a means of impressing 

 the necessity for uniformity of scale in thought, in measurement, and 

 in illustration, where such questions are discussed ; (ii) as pointing 

 the contrast between primary and secondary development ; and 

 (hi) as localising the study of primary mouldings in relation to the 

 growing point itself. 



More than 200 of the illustrations have been specially prepared for 

 this book. My own original drawings are initialed. Almost an equal 

 number were drawn for the first edition by Professor J. McLean 

 Thompson of Liverpool University, and these are signed by him. 

 Many beautiful French blocks have been borrowed from Figuier's 

 Vegetable World, and a considerable number have been taken with 

 permission of the publishers from Strasburger's Textbook. By arrange- 

 ment with the S.P.C.K., many of the excellent drawings of Fungi by 

 the late Professor Marshall Ward are embodied. They are taken from 

 his Diseases of Plants, now long out of print. The sources of these 

 illustrations, and of some others not mentioned here by name, are 

 specified in the rubrics, and their use is gratefully acknowledged. 



Finally, I wish to thank critics and friends who have, in print or 



verbally, suggested amendments to the Text : and in particular 



Dame Helen Gwynne-Vaughan, G.B.E., Professor W. H. Lang, and 



Dr. S. Williams. But I hold myself fully responsible for the text 



as it stands. 



F. O. BOWER. 



Ripon, 1939. 



