216 AQUATIC PHYCOMYCETES 



observations on the extraordinary change in size of the zoospores of 

 P. megastomwn during motility are correct (6.5 u. to 16.3 u.) a further 

 difference is found, for in P. olla they remained 5 by 3 [jl. Finally, no 

 "false proliferation" of the sporangium was noted in the present species. 



Phlyctidium brebissonii (Dang.) Sparrow 



Aquatic Phycomycetes, p. 149. 1943 



Chytridium brebissonii Dangeard, Le Botaniste, 1: 59, pi. 3, fig. 17. 1889. 

 Rhizophydium brebissonii (Dang.) Fischer, Rabenhorst. Kryptogamen-Fl., 

 1 (4): 97. 1892. 



Sporangium sessile, broadly urceolate or broadly ovoid, with an 

 apical collarette of from four to eight prominent plain teeth, wall 

 fairly stout, smooth, colorless; rhizoid a broad, nearly isodiametric, 

 apparently unbranched filament; zoospores numerous (one hundred 

 or more), ovoid, 2.7 \x in diameter, with a colorless eccentric globule 

 and a long flagellum, emerging in a compact mass through a large 

 apical pore; resting spore not observed. 



Parasitic on Coleoclwete scutata in culture dishes, France. 



It seems probable that if the conspicuous rhizoid were branched 

 in the host cell evidences of this would have been observed by Dan- 

 geard. The zoospores are cited as "2 \x 7" (2.7 jj.?) in diameter. Pos- 

 sibly a species of Rhizophydium. 



Phlyctidium spinulosum Sparrow 

 Mycologia, 25: 516, fig. 1, 2. 1933 



Sporangium sessile, spherical or slightly ovoid, colorless, generally 

 about 10 [i. in diameter, wall covered with short sharp spines 2 \i 

 high; haustorium a single unbranched slightly inflated tube, 10 u. 

 long by 3 \x in diameter; zoospores (usually about eight) 3 \x in diam- 

 eter, with a single globule and flagellum, escaping through a subapical 

 pore; resting spore not observed. 



Parasitic in Cladophora sp., United States (rare, occurring with 

 Phlyctochytrium quadricorne). 



An incompletely known form found by Sparrow (1933c: 518, pi. 

 49, fig. 12) in Cladophora sp. has a spherical sporangium about 15jx 



