200 AQUATIC PHYCOMYCETES 



35 u.; wall thick, hyaline, outer layer with broad-based spines. Sorus 

 epibiotic, spherical, 28-80 fx in diameter, wall yellowish brown covered 

 with small spines, formed at the end of an exit tube and at maturity 

 containing ten to one hundred triangular zoosporangia 13 — 21 [x high 



7-14 jx broad at the base. Zoospores not observed" (Canter, he. 

 cit.). 



Parasitic in Closterium lunula, C. dianae, C. costatum, C. kutzingii, 

 and Closterium sp., Great Britain. 



Micromyces intermedia (Canter), comb. nov. 



Micromycopsis intermedia Canter, Trans. Brit. Mycol. Soc, 32: 79, fig. 5. 

 pi. 10, figs. 9-10. 1949. 



"Prosorus spherical, 10.7-17.8 \l in diameter, wall brown, spiny, 

 granular or smooth; sorus epibiotic, sessile on the host wall or at some 

 distance from it; spherical, wall yellowish brown, covered with minute 

 blunt spines, splitting into four to six parts to expose the same number 

 of broadly triangular sporangia; zoospores twenty to thirty, oval (3.5 X 

 1.5 (x) with a conspicuous oil globule, and smaller refractive globule 

 at the side. Resting spores unknown" (Canter, loc. cit.). 



In Zygnema spp., Great Britain. 



Micromyces ovalis Rieth 1 

 Osterr. Bot. Zeitschr., 97: 516, figs. 1-12. 1950 



Synchytrium ovalis (Rieth) Karling, Mycologia, 45: 278. 1953. 



Prosorus ellipsoidal, up to 12-18 ;x long by 8 u, in diameter, the outer 

 wall bearing four to six rings of coarse, shark's-tooth-like spines which 

 in exceptional cases may be spirally arranged; sorus spherical or sub- 

 spherical, smooth-walled, forming four tetrahedral sporangia which 

 for the most part do not become free from one another, the inner wall 

 remaining connected, the sorus wall tearing apart at the line of contact 

 of the sporangia; zoospores numerous, somewhat spherical, about 1 a 

 in diameter with a posterior flagellum, escaping through one or two 

 pores on the sporangium wall into the host cell; resting spore probably 

 like the prosorus. 



1 See var. giganteus, p. 204. 



