PLASMODIOPHORALES 785 



sporangia or one or more cystosori ; schizogony reduced or lacking (?). 

 Zoosporangia numerous in a cell and usually grouped together, small 

 and variously-shaped; opening by a rupture of the wall. Zoospores 

 from sporangia pyriform. Germination of resting spores doubtful or 

 unknown at present" (Karling, 1942d: 58). 



Type species: Ligniera junci (Schwartz) Maire and Tison. 



In roots of aquatic and marsh plants. 



A poorly defined genus erected to include plasmodiophoraceous fungi 

 with loosely and variously aggregated resting spores that develop within 

 a single host cell and do not cause host hypertrophy. As Karling (1942d) 

 rightly conjectured, it appears "to be scarcely more than a convenient 

 dumping ground for species which cause little or no hypertrophy." 

 Cook (1933b) indicated that the zoospores are anteriorly uniflagellate 

 and that they function as isogametes. Both of these features are ques- 

 tionable and are in need of further study. 



SPECIES IN AQUATIC VASCULAR PLANTS 



Ligniera junci (Schwartz) Maire and Tison 



C. R. Acad. Sci. Paris, 152: 206. 1911 



Parasitic in Juncus spp., and a wide variety of aquatic, marsh, and 

 terrestrial plants. 



Ligniera isoetes Palm 

 Svensk. Bot. Tidsskrift, 12: 228, figs. 1-3. 1918 

 Parasitic in Isoetes lacustris. 



TETRAMYXA Goebel 



Flora, 67: 517. 1884 



Tliecaphora Setchell, Mycologia, 16: 243. 1924. 



"Resting spores usually in tetrads but often separating and lying 

 singly, or in diads and triads; variously shaped, giving rise to a single 

 nonflagellate (?) and amoeboid cell in germination. Plasmodia usually 

 small, becoming parietal in the host cell at maturity and cleaving into 

 uninucleate spore-mother cells or sporonts which usually divide twice 



