644 MINNESOTA BOTANICAL STUDIES. 



XXXIX. A RE-ARRANGEMENT OF THE NORTH 

 AMERICAN HYPHOMYCETES. 



Roscoe Pound and Frederic E. Clements. 



In working over the Hyphomycetes of Nebraska for the forth- 

 coming part 8 of the Flora of Nebraska, we were at once con- 

 fronted with the question how to arrange the group. In deal- 

 ing with the species reported from Nebraska we have been 

 compelled to go over all the genera and a large number of the 

 species reported from North America, and in so doing have 

 become aware of many grounds for dissatisfaction with the 

 prevailing arrangement. 



We might indeed have been content to follow the arrange- 

 ment of the Sylloge Fungorum, which has come into general 

 use. This system is admirably adapted to finding forms and 

 locating them in their proper place in the system. As a prac- 

 tical key, its utility is not to be questioned. But such an 

 arrangement does not commend itself, even in a group like the 

 Hyphomycetes. Moreover, in practice, the Saccardian system is 

 often somewhat unsatisfactory, so that it seemed to us at least 

 worth the while to make a further attempt to bring order from 

 the chaos prevailing in the group. When species have to be 

 "sought patiently under many genera,"* it would seem that 

 further labors to define the genera are not misspent. In no 

 group, indeed, are the genera more in need of thorough revis- 

 ion. Being composed solely of form genera — conidial and 

 chlamydosporous forms of Ascomycetes, with a few stray mem- 

 bers of autonomous groups such as Gymnoascaceae, Exobasidia- 

 ceae, etc., — the Hyphomycetes are properly enough left to drift 

 for themselves, and receive attention chiefly from collectors. 

 The diverse forms which the same fungus often assumes either 

 successively or at the same time, add greatly to the difficulty 

 of defining genera or even species. Fungi closely related in 

 their mature fructification differ widely in their conidial 



*Syl. Fung. 4:1. 



