CHYTRIDIALES 545 



Chytriomyces fructicosus Karling 

 Bull. Torrey Bot. Club, 76: 353, figs. 18-52. 1949 



"Sporangia hyaline to light brown, often appendiculate and usually 

 apophysate, variable in size and shape, almost spherical, 17-35 \i, oval, 

 31-42 X 37-50 [x, almost hemispherical, 15-55 \x diam., broadly and 

 narrowly pyriform, obclavate, citriform, elongate, or slightly anatro- 

 pous, with 1-2 low exit papillae or 1-3 tapering exit tubes, 8-12 fx broad 

 at the base by 10-60 \x long. Operculum saucer- to bowl-shaped, 4-8 \l 

 diam., non-persistent. Zoospores oval, 3.8-4.2 x 5.5-6 \x, with a hyaline, 

 spherical, 1.2-1.8 \x, refractive globule; swarming actively and briefly 

 in a vesicle outside of the sporangium. Apophysis variable in size and 

 shape, rarely spherical, 8-20 \x, oval, 8-15 x 20-25 \x, fusiform, 12-15 

 X 27-30 [jl, elongate, 18-20 x 30-32 \x, irregular or angular. Rhizoids 

 bushy in appearance and frequently branched, angles of branching 

 obtuse and frequently at right angles; main axes centered on the base 

 of the apophysis or arising at several points on the periphery, 3-8 \x in 

 diam., branches occasionally extending for a distance of 275 \x. Resting 

 spores light amber to greenish brown, usually spiny, occasionally verru- 

 cose or echinulate; spines up to 15 \x long by 3 \x wide at base; spherical, 

 18-30 \x, including spines, oval or slightly angular, with finely granular 

 content; germination unknown" (Karling, he. cit.). 



Saprophytic on chitinous substrata in soil and water, United States. 



About 18 per cent of the sporangia and resting spores were formed 

 from thalli which had developed from the germ tube of the zoospore 

 and not by expansion of the zoospore body itself. The type of develop- 

 ment seemed dependent upon the behavior of the nucleus of the encysted 

 zoospore. If it remained in the cyst a Rhizidium-\ike development ensued, 

 whereas if it passed into the germ tube the less typical method of 

 development was undergone. The sporangia are quite variable in shape 

 and may have one to three apophyses. 



As noted by Karling (1947d) in other species of Chytriomyces, a 

 single nucleus is present in the sporangial rudiment until the latter 

 reaches full size. 



