312 COMPARATIVE MORPHOLOGY OF FUNGI 



As in Venturia, there is now a rest period which lasts through the 

 winter. In spring, the binucleate cell develops in an unknown manner 

 ascogenous hyphae which form 8-spored asci (Fig. 207, B). 



This peculiar ontogeny may not be interpreted at present, since 

 Cryptomyces is still too isolated morphologically. In certain relations it 

 reminds one of Penicillium crustaceum as there the ascogenous hyphae, 

 so here the fertile hyphae grow like foreign bodies in the plectenchyma 

 of the fructification and parasitize it in a certain sense; this relation 

 finds its explanation in the fact that at that time only the tissue of the 

 fructification can furnish nourishment, since the leaf of the host is 

 already exhausted. It is also suggestive of the relations of the ooblastema 

 filaments to auxiliary cells in the red algae. 



In regard to the origin of the fertile hyphae, Cryptomyces Pteridis is 

 reminiscent of Systremma JJlmi; as in the latter, they are the apical cells 

 of the parenchyma of the fructification which, by renewed growth, change 

 the sclerotoid tissue body to true ascomata. Only in S. JJlmi this growth 

 takes place upward from the tissue body, while in C. Pteridis from above 

 down into the tissue body. It is possible that this localization of the 

 meristem at the top of the tissue body is connected with the acid require- 

 ments of the fertile hyphae. 



In form of fertile hyphae, C. Pteridis is almost unique. While in the 

 previously discussed forms, the ascogonia, with the exception of Sordaria 

 macrospora in the Sordariaceae, generally are helical, in C. Pteridis the 

 fertile hyphae (antheridia and ascogonia) are elongate. To use an 

 expression of Killian, they form a parallel thread type. It is possible that 

 they must be regarded as end forms in a sense which will be again met 

 in the Pezizales, in the Leotia-Spathularia series of the Geoglossaceae and 

 the Icmadophila-Baeomyces series of the discomycetous lichens, in which 

 the ascogonia (which alone are formed in these species, since the antheridia 

 are suppressed) gradually lose their specific form, finally becoming vege- 

 tative hyphae filled with reserves. In this manner, the fertile hyphae of 

 Cryptomyces may be regarded as an (ideal) step in the direction of the 

 pseudogamy which takes place in the Uredinales (e.g., in the aecia between 

 two specialized hyphae). 



The other forms so far studied give no answer to this question. In 

 Coccomyces hiemalis (Higgins, 1914), the leaf spot of cherry, and Phaci- 

 dium repandum on Galium rubioides (Satina, 1921), helical ascogonia with 

 trichogynes of the Polystigma type were observed. 



In Rhytisma acerinum, one of the Dermopeltinaceae of Hoehnel, the 

 ascogonia are elongate and no longer typical, while there are no antheridia. 

 The hyphae penetrate maple leaves in all directions from the spot of infec- 

 tion and fill the epidermal cells of the upper surface of the leaf, less often 

 those of the lower side, with a dense tissue. The walls between the 

 epidermal cells are broken and gradually dissolve so that the hyphal 



