576 AQUATIC PHYCOMYCETES 



face of the Nitella, attached to the apophysis at the isthmus. Rhizoids 

 elaborately developed, much branched, the ultimate branches with 

 blunt tips, attached to the apophysis near the isthmus or more frequently 

 to the isthmus by one main trunk. Resting spores near amber brown, 

 nearly spherical but slightly wider than tall, usually with 8-12 large, 

 rounded protuberances, rarely smooth, wall 2.8-4 u. thick, when ripe 

 with one large oil (?) globule surrounded by a layer of smaller spherical 

 bodies, 10-30 \x wide x 11-29 \x long, usually 18-21 \l wide x 16-19 u. 

 long; spore with an empty, basal, usually barrel-shaped, or sometimes 

 irregular apophysis, the walls of which are hyaline or nearly so; barrel- 

 shaped part about 12-19 \i wide x 8-15 u, long, but much smaller in 

 depauperate specimens, wall about 2.5 \x thick beneath the spore but 

 thinning to a mere membrane at the basal rhizoidal end. The empty 

 zoospore case becoming thick-walled and yellowish and remaining 

 attached to the base of barrel-shaped part. Germination not observed" 

 (Couch, he. cit.). 



Saprophytic in cells of Nitella hyalina, United States. 



Distinguishable from Nephrochytrium appendiculatum "by the more 

 or less disc-shaped sporangia connected with the nearly spherical apoph- 

 ysis by a narrow isthmus, the columella-like structure at the spo- 

 rangial base, the irregularly shaped pore through which the spores 

 emerge, and the stellate resting spores ..." (Couch, op. cit.). 



Nephrochytrium aurantium Whiffen 



Amer. J. Bot., 28: 41, figs. 1-26. 1941 



"Thallus monocentric, consisting at maturity of a much branched 

 rhizoidal system, an empty apophysis and an orange-colored zoospo- 

 rangium. Zoosporangia spherical, cylindrical, or much lobed, 12— 54(0. x 

 16-62 u.. Exit papillae, one or more in number, closed by a circular cap, 

 which is pushed out by the emerging zoospores. Apophysis, 6-23 u. X 

 7-30[jl, typically spherical, developing as an enlargement of the unbranch- 

 ed portion of the germ tube. Rhizoidal system, colorless, extensive, 

 much branched, continuous with the apophysis. Zoospore case orange- 

 brown in color, attached to the apophysis by its germ tube. Zoospores, 

 4-4.8 u., spherical, posteriorly uniciliate, each with a single orange- 



