PREFACE TO THE SECOND EDITION xi 



My sincere appreciation is expressed at this time to F. T. Brooks, 

 F.R.S., professor of botany, Cambridge University, and to Docent 

 Doctor H. E. Petersen, of the University of Copenhagen, for their 

 active sponsorship of my researches and their continuing interest. 



Finally, it is a genuine pleasure to acknowledge my great and lasting 

 indebtedness to Professor W. H. Weston, Jr., of Harvard University, 

 who, by his stimulating guidance and his love for and profound 

 knowledge of aquatic Phycomycetes, first aroused my interest in these 

 most curious organisms. 



F. K. S., Jr. 



Ann Arbor, Michigan 

 December, 1940 



PREFACE TO THE SECOND EDITION 



The second edition of Aquatic Phycomycetes has been extended to 

 include: (1) descriptions of those species of Pythium (in key form) 

 and of Phytophthora that are known to exist in nature as "water 

 molds"; (2) of genera of the Saprolegniaceae and citations of new 

 taxa described since Coker (1923) and Coker and Matthews (1937); 

 and (3) of the few desmid parasites belonging to the genus Ancylistes 

 of the Entomophthorales. A further addition is the inclusion of the 

 names and citations of species of Physoderma parasitic on marsh and 

 aquatic vascular plants. 1 With respect to the Plasmodiophorales, full 

 descriptions are given of those species parasitic in aquatic cryptogams. 

 As in Physoderma, citations only are included of plasmodiophoraceous 

 species in aquatic and marsh vascular plants. In both groups there is 

 so much need of careful morphological, life history and host range 

 studies that to present these species otherwise at this time seems 

 meaningless. 



The treatment and arrangement of the descriptions of most of the 

 fungi included here do not differ appreciably from those explained 

 in the Preface of the first edition. An effort has been made to assemble 



1 Subsequent to 1950. 



