CHYTRIDIALES 539 



KEY TO THE SPECIES OF CHYTRIOMYCES 



Sporangium not appendiculate 

 With one discharge pore 



Sporangium spherical, oval or ovoid, occasionally somewhat pyri- 

 form 



Globule of zoospore golden red C. aureus, p. 539 



Globule of zoospore hyaline 

 Zoospore spherical or oval, 2-3 u in diameter; sporangia up 

 to 30 [i in diameter 

 Sporangium spherical or slightly oval, apophysate; para- 

 sitic on Aphanomyces C. parasiticus, p. 540 



Sporangium spherical or broadly pyriform, nonapophy- 



sate; on Closterium C. closterii, p. 540 



Zoospore oval, 3-3.5 [x by 5-5.5 \i ; sporangia up to 60 \i in diam- 

 eter C. hyalinus, p. 541 



Sporangium broadly pyriform or transversely flattened 



Sporangia predominantly broadly pyriform, wall covered with 



abruptly tapering spines C. spinosus, p. 542 



Sporangia transversely flattened, somewhat reniform; wall 



smooth C. lucidus, p. 542 



With one to three discharge papillae or broad tubes ; wall with one 



to six solid pegs or spines C. stellatus, p. 543 



Sporangium appendiculate, that is, bearing part of the unexpanded 

 body of the zoospore 

 Sporangium with one discharge papilla 



Sporangium oval or obpyriform, with an extramatrical stalk, small 



(up to 1 3 [j. high by 1 5 y. broad) ; on diatoms C. tabellariae, p. 543 

 Sporangium extremely variable and irregular in shape, sessile, 

 large (up to 250 \i in diameter), wall with brownish thicken- 

 ings ; on chitinous substrata C. appendiculatus, p. 544 



Sporangium with one or two discharge papillae or one to three dis- 

 charge tubes C fructicosus, p. 545 



Chytriomyces aureus Karling 



Amer. J. Bot., 32: 363, figs. 28-45. 1945 



(Fig. 32 E-F, p. 554) 



"Sporangia golden-red, smooth, spherical (8-40 \x), or slightly oval 

 (10-20 x 12-23 fx); operculum apical or subapical shallow saucer- 

 shaped, 4-6 \l in diam. Zoospores oval, 3-3.5 X 5 fx, with a golden-red 

 refractive globule, 1.5-2 { i in diam.; flagellum 22-25 u, long; zoospores 



