356 AQUATIC PHYCOMYCETES 



ses, and with an extensive, branched rhizoid, up to 3.6 \x in diameter, 

 extending from distal apophysis, tapering to delicate points. Apophyses 

 spherical, ovoid or spindle-shaped, with smooth, hyaline membrane; 

 proximal apophysis 5.6-7.0, averaging 5.9 \x in diameter, distal one 

 4.2-21 .1, averaging 11.2 \x in diameter. Resting spores smooth, spheri- 

 cal, ovoid or irregular, 14.0-32.2, averaging 22.2 \x in diameter, with 

 2-layered, hyaline wall 3.0-5.0 \x thick; endospore 2.0-3.8 \x, exospore 

 about 1.0-1.2 \x thick; with finely granular cytoplasm, containing 1 to 

 several oleaginous-like globules; germinating by the formation of an 

 extramatrical, aculeated sporangium lacking an apiculus; liberating 

 zoospores" (Bartsch, he. cit.). 



Parasitic and saprophytic in zygospores of Spirogyra majuseula, S. 

 weberi, Bartsch (he. cit.), Spirogyra sp., Sparrow (1952d: 765, fig. 1 k) 

 United States; Spirogyra sp., Blytt (he. cit.), Norway; Spirogyra sp, 

 H. E. Petersen (1909: 409, fig. XIX; 1910: 543, fig. XIX), Denmark; 

 Spirogyra sp., Scherffel (1926a: 216, pi. 10, figs. 90-95), Hungary; 

 Spirogyra majuseula, Denis (1926: 19, fig. 3), France; Spirogyra sp., 

 Cejp (1932a: 1, pi. 1, figs. 1-4, pi. 2, figs. 1-2), Czechoslovakia; 

 Spirogyra sp., Shen and Siang (1948: 182, fig. 3), China; Spirogyra sp., 

 Mougeotia sp., Sparrow (1952a: 36), Cuba. 



Blyttiomyces helicus Sparrow and Barr 



Mycologia, 47: 551, figs. 22-23. 1955 



(Fig. 20 G, p. 330) 



Zoosporangium broadly ovate to globose, 16-33.5 \x high (including 

 the apiculus) by 14-26.5 [i in diameter, wall light brown and bearing 

 narrow low 0.8-1 \i thick helical bands which extend from the base to 

 the thick, light-brown apiculus 2-2.5 [i high by 4-6 \x in diameter; 

 endobiotic part coarse and extensive, consisting of an apophysis, 4-7 jj. 

 in diameter, from which emerges basally a rhizoidal axis 2.1-3 \x in 

 diameter, which branches distally; zoospores spherical, 4-4.8 \i in diam- 

 eter, with an eccentric, colorless refractive globule 1.6-2 u, in diameter, 

 and a long posterior flagellum, moving in the sporangium before 

 escaping through one, occasionally two, basal discharge pores, move- 



