660 AQUATIC PHYCOMYCETES 



Thallus with a simple, lobed, or branched basal cell; secondary 

 axes present and lacking pseudosepta, or absent, setae present 

 or absent; zoosporangium with a single apical discharge 

 papilla; gametophytes unknown Blastocladia, p. 678 



BLASTOCLADIELLA Matthews 



J. Elisha Mitchell Sci. Soc, 53: 194. 1937 

 (Figs. 39, p. 612; 45, p. 661) 



Rhopalomyces Harder and Sorgel, Nachrichten Gesell. Wiss. Gottingen, 

 Math.-Physik. KL, Fachgruppe VI (Biol.), (N. F.), 3(5): 123. 1938. Non 

 Corda et alii. 



Clavochytridium Couch and Cox, in Cox, J. Elisha Mitchell Sci. Soc, 55: 

 389. 1939. 



Sphaerocladia Stiiben, "Planta/" Archiv. wiss. Bot., 30(3): 364. 1939 



Thallus consisting either of a simple spherical swelling with a basal 

 complex of rhizoids or a more or less elongate unbranched basal cell 

 without pseudosepta, forming distally a single reproductive organ, the 

 whole anchored to the substratum by a system of branched holdfasts, 

 walls not giving a cellulose reaction; sporophyte plant bearing termi- 

 nally either a zoosporangium with thin walls, which discharges the fully 

 matured posteriorly uniflagellate zoospores through one or more pores 

 produced by deliquescence of papillae, or a resting spore having thick 

 two-layered walls (outer one variously sculptured) that completely fills 

 a thin-walled case; resting spore germinating to form posteriorly uni- 

 flagellate planonts which either give rise directly to new asexual or 

 sexual plants or at once encyst, cysts each developing endogenously four 

 posteriorly uniflagellate isogametes which emerge through a pore and 

 fuse in pairs, the resulting biflagellate zygote producing upon germi- 

 nation an asexual plant; gametophyte plant similar to the sporophyte, 

 dioecious, giving rise to posteriorly uniflagellate isogamous planoga- 

 metes. 



Thus far collected primarily only as saprophytes in soils from 

 southerly latitudes. 



KEY TO THE SPECIES OF BLASTOCLADIELLA 



Life cycle of the Euallomyces type, that is, involving isomorphic gener- 

 ations, sexual and asexual 



