PREFACE 



In the second volume of this work, pubhshed in 1922, the Agari- 

 cineae were divided into (1) the Aequi-hymeniiferae or Non- 

 Coprinus Type of fruit-body organisation, made up of five Sub- 

 types, and (2) the Inaequi-hymeniiferae or Coprinus Type, made 

 up of six Sub-types. Of the eleven Sub-types the first was 

 described in Volume II and eight more in Volume III. The two 

 remaining Sub-types, the Curtus and the Plicatilis, are described 

 in the first two chapters of the present volume. Thus a task 

 proposed nine years ago has at length been brought to completion. 



This volume is divided into two parts. Part I is devoted to 

 the record of some further observations on the Coprini, while Part II 

 treats of problems connected with social organisation and sex in the 

 Hymenomycetes and particularly in the Coprini. 



In a preliminary notice published in 1917, and in a more elabo- 

 rate thesis published in 1918, Mile Bensaude first demonstrated, by 

 a combination of experimental and cytological methods, that the 

 phenomenon of heterothallism occurs in the Hymenomycetes. The 

 species upon which she worked was a Coprinus, and it was her 

 stimulating papers that led to the experimental studies of sexual 

 phenomena in the Hymenomycetes, especially in the Coprini, which 

 have been carried out in my laboratory at Winnipeg. As some 

 acknowledgment of Mile Bensaude 's pioneer work, this Volume has 

 been dedicated to her. 



In Part II, Chapter I, which treats of social organisation in the 

 Higher Fungi, an attempt has been made to elucidate the physio- 

 logical advantages which accrue to the mycelia through the 

 existence of the numerous hyphal fusions which are so charac- 

 teristic of them. Here, perhaps, new ground has been broken. 



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