HYPHOCHYTRIALES 755 



cellulose and persistent, the cellulose discharge tube apical, up to 300 jj. 

 long by 10 [jl in diameter; rhizoids richly branched, arising from one or 

 more axes at the base of the sporangium; apophysis apparently lacking; 

 zoospores oblong-ellipsoidal, 8 u, long by 6 u. broad, with a single an- 

 terior flagellum about 20 [i long, formed in a vesicle produced at the 

 tip of the discharge tube; resting spore not observed. 



In soil, "flies," Nabel (loc. cit.), Haiti, Venezuela, Mexico, Jugo- 

 slavia; insect cases, Karhng (1943: 644), United States; insect wings 

 and legs, Karling (1944d: 393, figs. 20-34), Brazil. 



The fungus was recovered by Nabel on different types of bait (pri- 

 marily fruit flies) in water cultures to which soil had been added. It was 

 cultivated on agar but failed to form zoospores. 



Karling (1944d) found that in the majority of instances a single 

 rhizoidal axis was developed. Occasionally, completely extramatrical, 

 Rhizophlyctis-like thalli were formed and in one case the plant was 

 polycentric. Contrary to Nabel's observations, he found no vesicle 

 formed at spore discharge. 



Rhizidiomyces hansonii Karling 

 Amer. J. Bot., 31 : 396, figs. 35-64. 1944 



"Sporangia extramatrical, non-apophysate, with smooth, light to dark 

 brown walls, and yellowish to orange-tinted protoplasm; spherical 

 (10-60 [A oval or ellipsoidal (8-20 12-38 (a), or oblong (12-22 x 18- 

 35 [j.); content emerging through an exit tube, 20-150 [jl long, and 

 undergoing cleavage outside the sporangium; vesicular membrane 

 around spore mass lacking. Zoospores oval to slightly elongate, 4-4. 5 X 

 5.5-6.5 [L, with numerous yellowish to orange-tinted granules and one 

 or two minute globules; flagellum 8-10 \x long. True resting spores 

 unknown. Sporangia in old cultures often becoming dark brown, thick- 

 walled, 2-3 [j., and dormant ; later giving rise to zoospores in the same 

 manner as the more evanescent sporangia" (Karling, loc. cit.). 



Saprophytic in soil containing vegetable debris, chitinous material, 

 Brazil. 



See remarks on spore discharge under the species that follows. 



