LAGENIDIALES 923 



and spiny; protoplasm coarsely granular, including a large vacuole or 

 globule of hyaline material; germination unknown" (Karling, be. cit.). 



The genus was at first merely named by Karling (1942a: 33), without 

 accompanying diagnosis. It was described by him several months later 

 (1942b: 205) but as yet has not been validated by a Latin description. 

 Rozellopsis was erected for the Rozella-likQ fungi with biflagellate rather 

 than uniflagellate zoospores. At present both monosporangiate and 

 septigenous species are included. However, Karling considers (1942e: 

 14) the septigenous ones will be atypical of Rozellopsis, if their linear 

 series of sporangia are shown to have arisen by thallus segmentation 

 rather than by multiple infection. 



Karling placed the genus, with misgivings, in the Woroninaceae of 

 older authors. He did this primarily on the basis of its plasmodial 

 thallus and the anterior unequally biflagellate zoospores described by 

 Tokunaga (1933a: 25) for Rozellopsis simulans. Prowse (1951 : 404), who 

 does not regard the latter feature of any great significance in view of the 

 difficulty of observing details in moving spores, noted that in R. septig- 

 ena they were of the laterally biflagellate type, with the posterior 

 flagellum twice as long as the anterior. Waterhouse (1940: 1 1) described 

 the zoospores in R. waterhouseii Karling as somewhat similar but with 

 the anterior flagellum longer than the posterior one. Perhaps, if the 

 biflagellate "Rozellas" both monosporangiate and septigenous, had 

 been more thoroughly studied before a new genus was erected for their 

 disposition, questions as to the interrelationship of the species and the 

 relationship of Rozellopsis to other genera might be more easily an- 

 swered. Prowse (1954b) came to the conclusion that the genus cannot 

 satisfactorily be included either in the Plasmodiophorales, the Woron- 

 inaceae, or in the Olpidiopsidaceae and he believes that it might better 

 be regarded as a distinct family within the Phycomycetes. For the 

 present, until information is forthcoming on the resting spores of 

 monosporangiate species, it is probably best to retain it in the Olpidiop- 

 sidaceae. 



KEY TO THE SPECIES OF ROZELLOPSIS 

 Sporangia septigenate (in linear series); parasitic in Saprolegniaceae 



Parasitic in Saprolegnia R- septigena, p. 924 



Parasitic in Achlya R- simulans, p. 925 



