926 AQUATIC PHYCOMYCETES 



Rozellopsis waterhouseii Karling 

 Mycologia, 34:206. 1942 



"Sporangia terminal, spherical, up to 74 jjl in diam., clavate, oval, or 

 obpyriform with 1-3 apical or lateral exit papillae. Zoospores pyriform, 

 5-8 u, long with a few small refringent granules in the center or near the 

 posterior end ; flagella apparently laterally inserted (?) ; zoospores active 

 for 24 hours or more, or rounding up and encysting" (Karling, loc. cit.). 



Parasitic in sporangia of Phytophthora cryptogea and P. megasperma, 

 occasionally causing slight hypertrophy, Waterhouse (1940: 7, figs. 1-8), 

 Great Britain. 



The species (named in Karling, 1942a: 34) is based on a fungus which 

 Waterhouse (loc. cit.) described as close to "Pleolpidium inflatum." She 

 recognized, however, that, because of the biflagellate zoospores, some 

 other disposition of it might eventually be necessary. 



OLPIDIOPSIS Cornu 



Ann. Sci. Nat. Bot., V, 15: 114. 1872 

 (Fig. 75 A-F, p. 939) 



Olpidiopsis (Cornu) Fischer, Jahrb. wiss. Bot., 13: 363. 1882; Rabenhorst. 



Kryptogamen-Fl., 1 (4): 37. 1892. 

 Pleocystidium Fisch, Sitzungsber. Phys.-Med. Soc. Erlangen, 16: 66. 1884. 

 Diplophysa Schroeter, in Cohn, Kryptogamenfl. Schlesien, 3(1): 195. 1885. 

 Pseudolpidiwn Fischer, pro parte, Rabenhorst. Kryptogamen-Fl., 1 (4): 33. 



1892. 

 Pleotrachelus Zopf, sectio integri H. E. Petersen, Oversigt Kgl. Danske 



Vidensk. Selskabs. Forhandl., 1905 (5): 448. 

 Bicilium H. E. Petersen, Bot. Tidsskrift., 29 (4):357. 1909; Ann. Mycologici, 



8: 503. 1910. 

 Pseudolpidiopsis Minden, Kryptogamenfl. Mark Brandenburg, 5: 255. 191 1 



(1915). 



Thallus at first naked, later surrounded by a membrane, endobiotic, 

 holocarpic, forming the rudiment of the sporangium, the receptive 

 thallus, or the contributing thallus (companion cell); sporangium 

 spherical or ellipsoidal, smooth-walled or spiny, nontubular and unlob- 

 ed, with from one to several discharge tubes; zoospores formed within 

 the sporangium, biflagellate, without well-defined diplanetism; resting 

 spore thick-walled, smooth or spiny, formed asexually or after conju- 



