592 AQUATIC PHYCOMYCETES 



posterior flagellum; emerging through a lateral or subbasal slightly 

 elevated pore upon the dehiscence of an operculum 8 u. in diameter and 

 remaining in a compact quiescent group before assuming motility; rest- 

 ing spore not observed. 



Saprophytic on cellophane, in soil, Sparrow (loc. cit.; 1952b: 69), 

 Cuba. 



The species has a remarkably similar inoperculate counterpart in 

 Cladochytrhan setigerum Karling (p. 466). 



SEPTOCHYTRIUM Berdan 



Amer. J. Bot., 26:461. 1939 

 (Fig. 36 B, p. 590; fig. 37 C, p. 598) 



"Rhizomycelium intramatrical, predominantly polycentric, consist- 

 ing of elongate, septate and constricted filaments, intercalary swellings 

 and finely branched rhizoids. Zoosporangia variously shaped, opercu- 

 late, terminal and intercalary, with one (occasionally several) neck of 

 variable length. Zoospores posteriorly uniciliate, emerging in a globular 

 to ovoid mass and lying quiescent for a few moments before swimming 

 away; method of swimming rapid and darting. Resting spores terminal 

 or intercalary, formed in the same position as the sporangia or from 

 the intercalary swellings ; germination through a pore in the wall directly 

 into an operculate zoosporangium similar to the evanescent one or into 

 a tube at whose tip the contents are concentrated and cut off by a cross 

 wall to form the zoosporangium" (Berdan, loc. cit.). 



Saprophytic on various plant parts. 



In her 1942 paper (in which the development is described) Berdan 

 comments (p. 260) that, "So many variations occur in the development 

 of this chytrid that it is very difficult to describe any one type as defi- 

 nitely representing the normal." 



KEY TO THE SPECIES OF SEPTOCHYTRIUM 



Zoospores up to 8.7 u. in diameter; septations and trabeculae common- 

 ly formed in the rhizoids 

 Sporangium extremely irregular in shape; zoospore with a single 



globule S. variabile, p. 593 



