CHYTRIDIALES 201 



Parasitic in Mougeotia sp., Austria. 



In one instance a prosorus developed a discharge tube at the tip of 

 which the sorus was formed. Because of this Rieth considered it likely 

 that transitional forms between Micromyces and Micromycopsis exist. 

 In contrast to M. zygogonii, which may cause an increase in both length 

 and breadth of infected host cells, this species induces only abnormal 

 elongation. 



Micromyces cristata var. cristata (Scherffel), comb. nov. 



(Fig. 16 D-E, p. 196) 



Micromycopsis cristata Scherffel, Arch. Protistenk., 54: 202, pi. 9, figs. 

 65-68, pi. 10, figs. 69-76. 1926 



Prosorus spherical and 1 1—16 jx (mostly 14^.) in diameter or sphe- 

 roidal and 13-16 by 18-20 [j., with a thickened dark-brown wall, the 

 outer surface bearing a helical series of spines making from five to 

 six equidistant turns, occasionally smooth-walled or with irregularly 

 arranged spines, discharge tube cylindrical, clavate, or irregularly curv- 

 ed, never extending beyond the host wall; sorus compound, sessile, 

 spherical, equal in size to the prosorus, wall thickened, deep blackish 

 brown, the outer surface covered uniformly with short blunt spines; 

 soral wall at maturity splitting along three or four planes; soral seg- 

 ments very thin-walled, spherical or by mutual contact somewhat 

 polygonal ; sporangia spherical, 4 \i in diameter, amoeboid, with a 

 large colorless globule and a 6-8 \x long flagellum, escaping through 

 a pore; zoospores three to five in a sporangium, minute, actively swim- 

 ming; resting stage not observed. 



Parasitic or, perhaps, only saprophytic in Hyalotheca dubia, Scherffel, 

 (be. cit.), Hungary; Hyalotheca dissiliens, Cejp (1933a: 2, pi. 1, 

 fig. 4), Czechoslovakia. 



Micromyces cristata var. minor (Sparrow), comb. nov. 



Micromycopsis cristata var. minor Sparrow, Mycologia, 24: 273, fig. 1 d-e. 

 1932. 



Prosorus bearing a helical series of spines, occasionally smooth- 

 walled, 8.5-10.4 \l (usually 8 \i) in diameter; discharge tube narrowly 

 cylindrical, isodiametric; sorus sessile, 7.8 \x in diameter, brown, cov- 



