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COMPARATIVE MORPHOLOGY OF FUNGI 



and whether they join in pairs or fuse has not been determined on account 

 of technical difficulties. Hereupon they grow in nutrient solutions to a 

 large sprout mycelium whose cells cling together (Fig. 99, 13 and 14). 

 When they reach the host they put forth germ tubes between the epi- 

 dermal cells into the interior. 



The other species correspond to P. macrosporus, only in P. inundatus 

 on Apium graveolens, the chlamydospores are differentiated into summer 



Fig. 99. — Protomyces pachydermus. 1 to 3, 8, 9. P. macrosporus. 4 to 7, 10 to 15. 

 1 to 10. Germination of hypnospores. 11 to 14. Copulation and development of endo- 

 spores. 15. Young hypha with hypnospores. (1 X 540; 2, 3, 11, 12 X 670; 4 to 7 X 

 1,500; 8 X 520; 9, 10 X 300; 15 X 170; after Meyer, 1888, and Bilren, 1915, 1922.) 



and hypnospores. The summer spores germinate immediately after 

 formation; in them the endospore does not come out, however, but 

 degenerates in the interior of the chlamydospores into single endospores. 

 In the hypnospores, which only germinate after a winter's rest, germina- 

 tion proceeds as in P. macrosporus (Dangeard, 1906; Biiren, 1918). 



A second genus, Taphridium (Volkartia), differs from Protomyces in 

 that the chlamydospores are not formed irregularly in the deeper tissues 

 of the host but as a continuous layer under the epidermis. In the forms 



