r 



1908] EDGERTON—ANTHRACNOSES ;; 7 1 



0/ 



genera of ascomycetes. According to our present classification of 

 ascomycetes, no two of these genera are in the same family, while 

 some are in widely separated orders. The genera that are at present 

 known to be connected with the Gloeosporium-like conidial stage 

 are Gnomonia, Glomerella, and Pseudopeziza. In the following 

 pages, these different types will be taken up separately. 



Gnomonia type 



Klebahn (25) seems to have been the first to connect a Gloeo- 

 sporium with Gnomonia. As a result of his work on the sycamore 

 anthracnose, extending over several years, he gave a most interesting 

 discussion of the peculiar polymorphism of the fungus commonly 

 known as Gloeosporium nervisequtim. He studied the fungus both in 

 the field and in the laboratory on artificial media, finding the perfect 

 stage in the late winter and early spring on old diseased leaves that 

 had lain under the trees over winter. Later he was able to obtain 

 it in abundance by cutting out the anthracnosed spots on the leaves 

 and putting them out in wire netting to winter. According to him, 

 the perfect stage begins to develop in the fall and is mature about 

 Christmas or a little later. By careful examination of his material 

 and by comparison with other herbarium material, he w^as able to 

 identify it with Laestadia veneta Sacc. & Speg., which he showed 

 to be a species of Gnomonia, and named it Gnomonia veneta (Sacc. 

 & Speg.) Klebahn. 



Klebahn was also able to show that the conidial stage is poly- 



morphic. While 



all cases very similar, 



the manner in which thev are borne is different. The types that he 



found 



I. The conidia may be borne in acervuh under the cuticle on 



short basidia. 

 as Gloeosp 

 2. The 

 long basidia. Thi 



know 



Sacc- 



mis 



Gloeosporium platani 



(Mont.) Oud. Before Klebahn, both Leclerc du Sablox (29) and 

 J. Beauverie (5) had shown that this was but a form of G. nercise- 

 qiium. 



3- The conidia may be borne on twigs in pustules, being known 



