544 AQUATIC PHYCOMYCETES 



Sporangium oval or obpyriform with a basal unexpanded portion of 

 the cyst of the infecting zoospore persistent, its long axis oblique or 

 nearly parallel with that of the host, 4.3-13 \l high by 6-15 \x broad, 

 resting on a narrow, unbranched extramatrical stalk up to 13 \x in 

 length, with a blunt lateral or basal discharge papilla surmounted by 

 a convex operculum 4.3-8 \x in diameter; rhizoids branched, not taper- 

 ing; zoospores 5-30, spherical, 3 [x in diameter with a conspicuous 

 globule, emergence not observed; resting spore borne like the spo- 

 rangium, oval, 9.9-12 u. broad by 5.7-6^ high, with a thick, smooth 

 wall, germination not observed. 



Parasitic on Tabellaria fenestrata, Schroter (loc. cit.), Switzerland; 

 T.flocculosa, T. fenestrate Canter (he. cit.), Great Britain. 



Because of the operculate sporangium and extramatrical resting 

 spore, Canter transferred Schroter's species to Chytriomyces. 



Chytriomyces appendiculatus Karling 

 Bull. Torrey Bot. Club, 74: 335, figs. 16-37, 43-48. 1947 



"Sporangia appendiculate, smooth, hyaline when young, but usually 

 becoming brown with age, highly variable in size and shape, rarely 

 spherical, 10-80 u., flattened or oval, 10-50 x 30-90 u., oblong, 10-20 



30-50 \l, irregularly pyriform, 20-180 < 35-250 \x, slightly bean- 

 shaped, tilted, irregular and lobed with a 1-3 u. thick wall; operculum 

 non-persistent, shallow saucer-shaped, 6-14 \x diam. Zoospores oval 

 4-5 X 6-6.5 \x, with a conspicuous, 1.8-2.8 \x diam., hyaline refractive 

 globule; flagellum 28-32 \x long. Rhizoids coarse, main axes up to 18 (x 

 in diam. in large thalli, branched, usually becoming thick-walled with 

 age. Resting spores smooth and usually appendiculate, spherical, 10-25 u., 

 oval, 10-15 X 18-24 u., predominantly irregular with a 2.5-5 [x thick, 

 brown wall ; content coarsely but evenly granular with a central vacuole, 

 emerging through a pore in the wall during germination and forming 

 a superficial zoosporangiuirf (Karling, loc. cit.). 



Saprophytic on chitinous substrata in fresh water, muck, and moist 

 soil, Karling (loc. cit.; 1948c: 508), United States. 



One of the peculiarities of this very distinct species is the tendency 

 for some sporangia to form large amounts of "slime" beneath the area 

 of discharge. In some material no vesicle was formed. 



