LAG EN IDI ALES 943 



Parasitic in hyphae of Aphanomyces sp., Dangeard (be. cit.), France; 

 Butler (be. cit.), India; Minden (1915: 267), Germany; Petersen (be. 

 eit.), Denmark; Aphanomyces laevis, Karling (1949a: 275), United 

 States; Aphanomyces laevis, Shen and Siang (1948: 200), China. 



Another interpretation of this species has been supplied by Whiffen 

 (1942b: 609). It is based on a parasite of Aphanomyces cladogamous 

 which could not be induced to infect A. laevis. Her diagnosis is given 

 below. The interested investigator can decide which fungus he wishes 

 to call O. aphanomycis. Our impression is that Whiffen's species should 

 probably be segregated as new, rather than any attempt be made to 

 identify it with Cornu's poorly known form. 



Olpicliopsis aphanomycis Cornu, sensu Whiffen 

 Amer. J. Bot., 29: 609, figs. 4, 10, 24-26. 1942 



"Zoosporangia 34.2 to 94.05 \x, one or two, sometimes more in swel- 

 lings of the host hyphae which are usually unilateral. Zoospores biflagel- 

 late. Resting bodies oval, 24.6 x 28.7 \x to 36.9 x 43.05 \x, or spherical, 

 13.2 to 44.46 \x, covered with broad-based spines, 2.1 to 4.1 \x in length; 

 exospore wall 4.1 \x thick, endospore wall 2.3 jjl thick; companion cell 

 lacking" (Whiffen, be. cit.). 



Parasitic in Aphanomyces cladogamous, not capable of infecting A. 

 laevis, United States. 



Olpidiopsis gracile (Butler) Karling 



Simple Holocarpic Biflagellate Phycomycetes, p. 47. 1942 



(Fig. 76 B, p. 960) 



Pseitdolpidium gracile Butler, Mem. Dept. Agr. India, Bot. Ser., 1: 131, 

 pi. 7, figs. 1-8. 1907. 



"Zoosporangia solitary or numerous, up to 40 in a single swelling, 

 hyaline, smooth or spiny, spherical, 4-52 \x, with 1 to 5 contorted and 

 swollen exit tubes of varying lengths which may project considerably 

 beyond the surface of the host cell. Zoospores, isocont (?), hyaline, 

 obclavate, elongate, and somewhat curved with one to several minute 



