CHYTRIDIALES 553 



smooth, hyaline, content composed of small globules. Germination 

 unknown" (Canter, he. cit.). 



Parasitic on Sphaerocystis schroeteri and Kirchneriella obesa, Great 

 Britain. 



Canter (he. cit.) points out that the sporangium and resting spore of 

 this species develop from both the cyst of the zoospore and its germ 

 tube, a parallel situation to that in the inoperculate genus Dangeardia 

 (p. 319). While she recognizes that to include the species in Zygorhizid- 

 ium strains the concept of that genus, until other related forms are 

 discovered, she prefers to leave it there. 



RHOPALOPHLYCTIS Karling 



Amer. J. Bot., 32: 363. 1945 



(Fig. 32 B, p. 554) 



"Thallus monocentric, eucarpic, consisting of an extramatrical spo- 

 rangium and an intramatrical rhizoidal system. Sporangia operculate, 

 stalked or sessile, septate or continuous. Zoospores posteriorly uniflagel- 

 late, emerging from sporangium and swarming in a vesicle. Resting 

 spores unknown" (Karling, he. cit.). 



A monotypic genus, the species of which has been found only on 

 chitinous substrata. 



Although not exhibiting the type of development found in Podo- 

 chytrium, mature plants of Rhopahphlyctis, with their basal sterile part, 

 resemble those of that genus. Rhopahphlyctis may be distinguished from 

 the similar-appearing Cylindrochytridium by its extramatrical sporan- 

 gium, which develops from the body of the encysted zoospore, and by 

 the absence of an apophysis. 



Rhopalophlyctis sarcoptoides Karling 

 Amer. J. Bot., 32: 363, figs. 1-26. 1945 



"Thalli numerous, up to 500 on one host. Sporangia hyaline, smooth 

 with fairly thick (1.5 \x) walls, obpyriform (10-70 X 15-90 u.), clavate 

 (12-40 x 35-180 \x), spherical (8-40 (x), or elongate, continuous or 

 septate, sessile or stalked, base of stalk sometimes expanded irregularly 



