LAGENIDIALES 941 



elongated, slightly inequilateral, with two cilia attached at or near the 

 anterior end. Oospores dark grey, with one, sometimes two, antheridial 

 cells; oospores surrounded by a thick endospore and a thin warty 

 exospore, spherical to oval, sometimes elliptical, up to 116 x 84 u., 

 average 50 ijl in diameter; antheridia spherical, less commonly oval, 

 average diameter 20 ;x, with a smooth, colorless wall. Germination of 

 oospores not observed" (Barrett, loc. cit.). 



In hyphae of Saprolegnia ferax, Barrett (loc. cit.), S. monoica, Graff 

 (1928:159), United States; Saprolegnia sp., Fischer (as Olpidiopsis 

 saprolegniae, 1892: 38), Minden (1915: 263), Germany; Saprolegnia sp., 

 Achlya sp., Petersen (as Olpidiopsis saprolegniae, 1909: 404: 1910: 539, 

 fig. 28b), Denmark. 



Placed in synonymy with Olpidiopsis inerassata by Karling (1942e), 

 see remarks under that species (above). 



Olpidiopsis luxurians Barrett 



Ann. Bot. London, 26:231, pi. 23, figs. 1, 5-7, 10-14, 17, 21b, 22; pi. 24 

 figs. 24-25, 28-30; pi. 25, figs. 43, 45; pi. 26, figs. 74, 76-90. 1912 



"Sporangia single or multiple, formed in terminal or intercalary 

 swellings of the host hyphae, oval to spherical, very variable in size, 

 with one to three exit tubes extending considerably beyond the wall of 

 the host; zoospores rather small, elongated, with two cilia attached at 

 or near the anterior end. Oospores spherical, with one or two, rarely 

 three, antheridia, with a thick endospore and a thin exospore provided 

 with numerous conical spines up to 2.5 \x in length; oospores 25-50 jjl in 

 diameter, contain one or more large oil globules; antheridia spherical, 

 frequently oval to elliptical, 10-25 \x in diameter, with a smooth color- 

 less wall. Germination of oospores not observed" (Barrett, loe. cit.). 



Parasitic in Aphanomyces laevis, Barrett (loc. cit.), United States; 

 in hyphae of Aphanomyces sp., Sparrow (1952c: 105), Cuba. 



From the coarseness of the spines on the resting spore, the species 

 appears to be intermediate between Olpidiopsis fusiformis ("0. minor") and 

 O. saprolegniae. Barrett states it could not be transferred to hosts on 

 which O. fusiformis ("O. minor") had been reported. This has been 

 verified by Shanor (1940). 



