516 AQUATIC PHYCOMYCETES 



Chytridium oedogonii Couch 

 J. Elisha Mitchell Sci. Soc, 54: 256, pi. 24. 1938 



Sporangium usually ovoid and broadest in its distal half, 14 45 \x 

 high by 7.5-17.6 \x broad, attached by a narrow isthmus to the small 

 unexpanded zoospore case from which it has arisen as a lateral out- 

 growth, with a low apical papilla surmounted by a shallowly convex 

 operculum; rhizoidal system arising from a spherical, 6-1 6^. in diameter, 

 or oval, 7.5-12.5 by 16-22 u., subsporangial apophysis, consisting of a 

 system of rarely branched, isodiametric threads 1.5-5 \x broad; zoo- 

 spores 4-5.5 [j. in diameter, with a basal or lateral (rarely two) globule 

 and long flagellum, escaping individually after dehiscence of the oper- 

 culum or forming a temporarily motionless cluster at the orifice before 

 swimming away; resting spore endobiotic, spherical, or slightly flattened, 

 10 \i by 15-31 (j. or more, with a smooth thick (1.2 jx) hyaline to yellow- 

 ish brown wall and one or more large refractive globules, germination 

 not observed. 



Saprophytic on Oedogonium sp., Couch (be. cit.), United States; 

 Oedogonium sp., Canter (1950d: 354, figs. 1-3, pi. 28, 29), Great 

 Britain. 



Chytridium kolianum Domjan 



Folia cryptogam., 2 (1): 27, pi. 1, figs. 88, 90-92, 101-106. 1936 



Sporangium sessile, spherical, subspherical, or ellipsoidal, 17.5 \x in 

 diameter by 12.5-20 \x high, wall smooth, thin, even, with the cyst of 

 the infecting zoospore persisting as a subapical or lateral hemispherical 

 refractive somewhat thick-walled appendage; rhizoids not well develop- 

 ed, branched, arising from the base of an endobiotic subsporangial 

 somewhat ellipsoidal swelling, 10-22 [i in diameter by 12.5-25 [j. high; 

 zoospores typically chytridiaceous, 5 \jl in diameter, emerging after the 

 dehiscence of a persistent adherent operculum formed from the whole 

 upper part of the sporangium; resting spore not observed. 



Saprophytic on Spirogyra, Zygnema, Hungary. 



The species differs from Chytridium schenkii in the shape of the spo- 

 rangium and the larger operculum, from C. gibbosum in the shape of the 

 sporangium and the evenness of its contour, and from C. aggregatum 

 by the presumably colorless wall of the cyst. 



