CHYTRIDIALES 507 



base a thick-walled, goblet-like sterile portion from which a short peg- 

 like hyaline stalk emerges, the latter not penetrating the host wall but 

 merely attached to it; zoospores 5 \jl in diameter, uniflagellate, with a 

 single colorless oil globule, escaping upon the dehiscence of the opercu- 

 lum; resting spore not observed. 



On Stigeoclonium sp. (gelatinous sheath ?), United States. 



Aside from its arched habit, the organism superficially resembles 

 Podochytrium clavatum Pfitzer, especially in the possession of a thin 

 sterile basal portion. The presence of an operculum, however, as well 

 as the character and mode of attachment of the sporangium, sharply 

 demarks it from Podochytrium, as well as from other species of Chytrid- 

 ium. It is probably saprophytic on the gelatinous sheath of the alga, since 

 no disintegration of the contents of those cells bearing sporangia was 

 noticed. 



Chytridium epithemiae Nowakowski 

 Cohn, Beitr. Biol. Pflanzen, 2: 82, pi. 4, figs. 12-13. 1876 



Sporangium broadly subglobose, with a prominent rounded apiculus, 

 12 [x in greatest diameter, prolonged basally into a narrow stalk which 

 rests with its knoblike tip on the surface of the host cell, wall somewhat 

 thickened, colorless, smooth; rhizoids not observed; zoospores not 

 observed, probably few, emerging upon the dehiscence of a subapical 

 convex operculum; resting spore not observed. 



On Epithemia zebra, Germany. 



Nowakowski regarded the apical protuberance as a second, non- 

 functional, operculum. It is more likely an apiculus similar to that 

 formed in Sporophlyctis, Blyttiomyces, and several other chytrids. 



The fungus on Melosira and Tabellaria doubtfully referred to this 

 species (Sparrow, 1933a: 68, fig. 1 d-f) is now considered distinct from 

 it. See Chytridium nodulosum, below. 



Chytridium nodulosum Sparrow 



Aquatic Phycomycetes, p. 338. 1943 



(Fig. 31 H, p. 496) 



Sporangium ovoid to pyriform, 6-13 [jl in diameter by 10-15 \x in 



length, with an apical operculum 5 jj. in diameter and a subapical round- 



