xii PREFACE TO THE SECOND EDITION 



descriptions of all taxa published since then. Arbitrarily, the date limit 

 of January 1, 1955, was established, at which time the contents were 

 in a sense "set." Literature subsequent to that date, however, has not 

 been omitted, but in most instances (such small groups as the Mono- 

 blepharidales excepted) no provision is made in the keys and body of 

 the text for new taxa and results of more recent investigations. Those 

 taxa published since the deadline date, usually through 1957, are given 

 under the heading of "Recently Described Taxa" at the end of the 

 descriptions of valid species. By means of footnotes, every effort has 

 been made, even in the final page proof, to incorporate references 

 to new investigations. For more ready reference, the format of the 

 "List of Substrata" has been revised. No attempts have been made to 

 tackle the nomenclatorial problems of hosts, and the binomials are 

 usually those given by the particular investigator. 



If any doubt exists as to the distinctiveness of the taxon, it has not 

 been placed in synonymy but separated by rules from the description of 

 the form to which it is related. Thus, the reader can make his own 

 decision in the matter. Duplication of pertinent facts throughout is 

 usually intentional since it is not expected that the volume will be read 

 as a whole but, rather, will be consulted at random as the need arises. 



Changes in locality names from the first edition are as follows: 

 Great Britain substituted for England; Austria and Czechoslovakia 

 no longer included under Germany. 



I am indebted to various persons in the preparation of this edition. 

 First and foremost I wish to express my thanks to the Dean and Execu- 

 tive Board of the Horace H. Rackham School of Graduate Studies of 

 the University of Michigan for their financial aid and warm support 

 of this entire project from the preparation of the manuscript through 

 the issuance of the volume. 



J. N. Couch has kindly scrutinized the treatment of the Saproleg- 

 niaceae and has supplied revised descriptions of the Coelomomycetaceae. 

 J. T. Middleton went over the key to Pythium and then generously 

 consented to the adoption of his style of presenting it; Grace Water- 

 house made suggrstions with respect to Phytophthora as did Ralph 

 Emerson for the chapter en the Blastocladiales. Their comments 

 and suggestions are here gratefully acknowledged. The responsibility 



