CHYTRIDIALES 355 



develops from the distal portion of the zoospore cyst, and one or more 

 endobiotic apophyses, the distal one of which bears a branched rhi- 

 zoidal system; sporangium inoperculate, epibiotic, uni- or multiporous, 

 the pores subapical, delimited from the endobiotic system by a septum; 

 zoospores uniflagellate with a single globule, formed within the sporan- 

 gium; resting spore endobiotic, variable in shape, formed by growth 

 and encystment of an apophysis, upon germination forming an epibiotic 

 zoosporangium. 



Parasitic on algae (Conjugatae), saprophytic on pollen. 

 The generic concept has been expanded to include forms with more 

 than one discharge pore. 



KEY TO THE SPECIES OF BLYTTIOMYCES 



Sporangium wall ornamented 



Sporangium wall covered with short spines ; with a single subapical 



or lateral discharge pore B. spinulosus, p. 355 



Sporangium wall bearing a series of low helical bands ; with one or 



two basal discharge pores B. helicus, p. 356 



Sporangium wall smooth B. laevis, p. 357 



Blyttiomyces spinulosus (Blytt) Bartsch 



Mycologia, 31 : 559, figs. 1-24. 1939 



(Fig. 21 A, p. 360) 



Chytridium spinulosum Blytt, Vidensk. Selsk. Skr. Christiana (Mat. -Nat. 

 KL), 1882 (5): 27. 



"Zoosporangia multispored, aggregated, globose, inoperculate, hya- 

 line, aculeated, 14.2-28 x 16.8-32.3, averaging 23.4 [i in diameter x 

 28.2 [x high exclusive of apiculus; with a single lateral exit pore about 

 40° from apex; aculei narrow, hyaline, about 0.5-2.0 [j. long, with 

 rounded apices; apiculus cuculate, hyaline, smooth-walled, 5.6 jj. in 

 diameter x 3.5-4.9, averaging 3.8 u, high. Zoospores spherical to ovoid, 

 hyaline, 4.2-7.0 u. in diameter, with a large, clear, refractive globule; 

 flagellum approximately 25 \x long; zoospore case becoming thickened 

 distally, persisting as sporangial apiculus after germination. Intrama- 

 trical portion of thallus coarse, extensive; consisting of 2 tandem 

 apophyses separated by zygospore wall of host, rarely with 3 apophy- 



