CHYTRIDIALES 595 



Septochytrium plurilobulum Johanson 



Amer. J. Bot., 30: 621, fig. 1. 1943 



(Fig. 36 B, p. 590) 



"Rhizo mycelium extensive and coarse with septations and trabeculae 

 extending partly or completely across the irregular tenuous portions. 

 Zoosporangia terminal or intercalary, hyaline, smooth, spherical, (11- 

 1 13 [jl in diameter, average 45-55 \i), oval, ellipsoidal, broadly pyriform, 

 with one to several short broad (7 \i), or long (33-38 u,) exit tubes; 

 operculum oval, spherical, 3.75 to 7 jj. in diameter. Zoospores oval to 

 spherical, (7-8 u,, average 7.7 u,) with numerous minute refractive glob- 

 ules which impart a grayish granular appearance to the spores; emerg- 

 ing fully developed and lying quiescent for a few moments in a globular 

 mass at the mouth of the exit tube before swimming away. Resting 

 spores usually terminal, irregular, and deeply lobed, 15-43.5 \x in great- 

 est diameter; of a greenish gray color, with a dark, smooth, thick wall 

 2.62-7 u, in thickness; containing one to several small or large refractive 

 globules; content emerging slowly in germination and developing into 

 an evanescent, thin-walled zoosporangium on the surface of the spore" 

 (Johanson, loc. cit.). 



Saprophytic in leaves of the striped maple, corn, and other grass 

 leaves, United States. 



Septochytrium macrosporum Karling 



Amer. J. Bot., 29: 616, figs. 1-15. 1942 



"Thallus predominantly polycentric, occasionally monocentric. Rhi- 

 zomycelium unusually coarse, richly branched, rarely septate, with 

 thick walls which stain brick-red to reddish-lavender with chloro-iodide 

 of zinc; tenuous portions apart from rhizoids 5 to 15 [j. in diam. ; rhizoids 

 numerous and richly branched; intercalary enlargements broadly or 

 narrowly spindle-shaped, elongate, fusiform, and irregular. Zoospo- 

 rangia terminal or intercalary, delimited from remainder of thallus by 

 cross septa, non-apophysate, spherical, 1 5-280 u., pyriform, 30-50 \i 

 x 70-190 [x, obpyriform, broadly fusiform, obclavate, uteriform [sic], 

 and sometimes irregular; hyaline and smooth; opercula 9-16 [i in diam. 

 Zoospores spherical, 1 1-13 u,, average 12.2 u,, with one larger, 2.5-3.5 u,, 



