CHYTRIDIALES 173 



ROZELLA ENDOCHYTRII Karlillg 



Torreya, 41: 106. 1941 



"Sporangia solitary in a host cell, spherical, 15-200 \x, oval, elongate, 

 pyriform and irregular, depending on the size and shape of the host 

 cell; wall of sporangium usually indistinguishable from that of the 

 host, hyaline and smooth with one to several exit papillae, 2-6 u, high. 

 Zoospores obclavate, 3.4-4 [jl x 1.5 \x, aguttulate but with optically 

 denser apical and basal regions which give them a characteristic ap- 

 pearance; swirling in the sporangium before dehiscence; emerging in 

 a stream and becoming actively motile in a few seconds. Resting spores 

 unknown" (Karling, 1942b: 200). 



Parasitic but not causing apparent hypertrophy in sporangia of 

 Endochytrium operculatum, Karling (he. eit.), United States; Karling, 

 (1944f: 644), Brazil. 



The species has been described in developmental detail by Karling 

 (1942a: 31, figs. 25-47). 



Rozella polyphagi Sparrow 



Mycologia, 30: 377. 1938 

 (Fig. 12 F-G, p. 124) 



Pleolpidium polyphagi Sparrow, Trans. Brit. Mycol. Soc, 18:215. 1933. 



Sporangium colorless, spherical, completely filling the often mark- 

 edly swollen prosporangium of the host, 20-48 \x in diameter, possess- 

 ing at maturity from two to six prominent papillae 4-8 \x in diameter, 

 through which the innumerable minute posteriorly uniflagellate nar- 

 rowly ovoid zoospores 2-3 fj. long by 1.5-2 [i in diameter, with a 

 single globule, are discharged; resting spore not observed. 



Parasitic in prosporangia of Polyphagus laevis, Great Britain. 



The species was described and figured in Sparrow (1936a: 426, pi. 

 14, figs. 19-20). 



Scherffel (1925b: 6, pi. 1, fig. 10) observed in the prosporangia of 

 Polyphagus parasiticus a brownish rough-walled resting structure. 

 Though the structure may be the resting spore of Rozella polyphagi, 

 the presence on it of a delicate rhizoid makes this improbable. 



