conform with a definite term, and the beginner must be governed accordingly. 



While the writer is particularly indebted to Saccardo's "Sylloge Fungorum,*' 

 he is also indebted to Thaxter's "Monograph of the Laboulbeniaceae," and his 

 "Preliminary Diagnoses of New Species of Laboulbeniaceae," II-VI, for the 

 material for the ke}- to this group. The treatment of the Pezizales is largely 

 that of Rehm's "Discomyceten," modified by the inclusion of the lichens. From 

 F.ngler and Prantl's "Pflanzenfamilien," material has been drawn in the mono- 

 graphs of the bacteria by Migula, of phycomycetes and other groups by Schroter 

 and Lindau, and especially of the lichens by Zahlbruckner. The writer is also 

 under heavy obligation to Dr. Edith Clements, for the preparation of the Glos- 

 sary, and for much other work of preparation and of publication. His thanks 

 are also due to Professor Raymond J. Pool for assistance in the original mimeo- 

 graph copies. 



Frederic Edward Clements. 



The University of Minnesota, 

 June I, 1909. 



