LAGENIDIALES 945 



268), soil, Remy (1948: 214), Germany; P. oryzae, Tokunaga (1933a), 

 Japan ; Pythium sp., Sparrow (1936a: 425), Great Britain; Pythium sp., 

 Karling (1949a: 275), United States. 



"Causing oval, spherical, obpyriform or balloon-shaped enlargements 

 at the end of the host hyphae or in lateral diverticula, and occasionally 

 leading to septation of the hyphae" (Karling, op. cit., p. 47). 



Neither Minden nor Sparrow was certain of their identifications. The 

 fungus occurring on Pythium but included by Dangeard (1 890-91 b: 90) 

 under Olpidiopsis aphanomycis may be referable to this species. 



Olpidiopsis curvispinosa Whiffen 

 Amer. J. Bot., 29: 610, figs. 1, 5-6, 21. 1942 



"Zoosporangia one to many in terminal or intercalary swellings of the 

 host hyphae, spherical to oval in shape, 12 to 68 u. in longest diameter, 

 cellulose wall smooth or with short bristles, one to three exit tubes. 

 Zoospores with numerous small oil globules, elongate and somewhat 

 reniform, biflagellate, flagellae of about equal length, attached near 

 anterior end of spore. Resting spores, consistently with a companion 

 cell, spherical to oval, 17 to 24 \x in longest diameter, containing one 

 large oil globule surrounded by vacuolate protoplasm. Exospore wall 

 with curved spines up to 5 \x in length. Companion cell spherical or oval, 

 14 to 20 [jl, smooth or with short, closely set spines" (Whiffen, loc. cit.). 



Parasitic on Pythium sp., United States. 



Characterized by the bent, flexuous-appearing, intertwining spines on 

 the resting spore. 



Found capable of parasitizing Pythium torulosum by Whiffen (op. cit., 

 p. 611). 



Olpidiopsis brevispinosa Whiffen 



Amer. J. Bot., 29: 610, figs. 2, 14, 22, 27. 1942 



"Zoosporangia one to many in terminal or intercalary swellings of 

 the host hyphae, swellings up to 125 \x in diameter. Zoosporangia 10.68 

 to 68.40 \i in longest diameter, wall smooth or with short bristles, with 

 one to three exit tubes. Zoospores with numerous oil globules, elongate 

 and somewhat reniform, biflagellate, the flagellae of about equal length, 



