206 



FUNGOUS DISEASES OF PLANTS 



Klebahn in his investigations of this fungus ascertained that 

 when the leaves are wintered over under suitable conditions of 

 moisture an ascigerous stage is developed the following spring. 

 This stage proved to be a Pseudopeziza ; that is to say, a 

 Pseudopeziza was one of the most abundant of the perithecial 

 stages found on wintered leaves. The spores of other perithecial 

 forms yielded upon inoculation of the growing leaves no result, 

 whereas spores of the Pseudopeziza developed in due course of 



Fig. 79. Anthracnose on Currant Leaf. (Photograph by 

 F. C. Stewart) 



time the Glceosporial stage upon growing parts. The ascigerous 

 stage develops as a small fungous body of rapidly growing tissue, 

 completely immersed in the leaf, and more or less surrounded by 

 the old hyphse of the Glceosporial form. With further develop- 

 ment the epidermis is ruptured and the apothecium opens as a 

 fleshy disk-shaped structure, the basal portions of which consist 

 of more or less pseudoparenchymatous tissue from which arise 

 numerous asci and paraphyses. The basal portion remains in 

 part surrounded by thick-walled cells of the old mycelium, as 



