PREFACE TO THE FIRST EDITION 



In the more than two and one-half decades which have ensued 

 since the completion of publication of Minden's treatment of the 

 lower, primarily aquatic, groups of Phycomycetes in Kryptogamen- 

 flora dcr Mark Brandenburg, considerable new material has been accu- 

 mulated about these curious and oftentimes very unplantlike organisms. 

 The later researches, added to those of the earlier period of activity, 

 which might well be considered to have terminated with Minden's 

 contributions to the field, have resulted in the bringing to light of a 

 rather rich and certainly a remarkably diverse flora composed of a 

 hitherto unsuspected number of species. New types of sexuality and 

 life histories have been discovered, and much has been learned of the 

 nuclear phenomena; methods of cultivation have been evolved and 

 other material of general biological interest made available. Coker 

 (1923) has provided an invaluable aid to the student of the Sapro- 

 legniaceae in his monograph of that family. Furthermore, the aquatic 

 as well as the amphibious and terrestrial species of the important genus 

 Pythium have been dealt with in recent years by Miss Matthews (1931). 

 Since the authoritative monographs of Coker and Miss Matthews are 

 in English and of relatively late date and, in addition, since they deal 

 with well-defined compact groups the reader is referred directly to them. 

 There remains, however, a not inconsiderable number of organisms 

 that have not been touched upon by either of these authors or by students 

 of special groups (Kanouse, 1927; Indoh, 1940; and others), including 

 in particular the large and notoriously difficult order of the Chytridiales. 

 The present volume is intended to give an account of the Phycomy- 

 cetes, other than the Saprolegniaceae and Pythium, that occur in fresh 

 and marine waters. Any biological treatise that attempts to circumscribe 

 organisms primarily on the basis of their habitat inevitably encounters 

 difficulties. These have not been overcome here. In general, groups 

 whose members are predominantly inhabitants of terrestrial host 



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