418 AQUATIC PHYCOMYCETES 



usually arising at several points on the apophysis, relatively fine and 

 richly branched, rarely extending more than 150 [x in extent. Zoospores 

 oval, 3 X 4 [i., with a small (0.8-1.2 \x) refractive globule lying slightly 

 toward one side, emerging as a globular mass which becomes enveloped 

 by a vesicle in which the individuals swarm for several minutes before 

 breaking out and swimming away; flagellum 28-30 \x long. Resting 

 spores hyaline, oval (15 x 18 [x), elongate (9 x 25 \i), and slightly 

 flattened, or spherical (12-18 \i), with several large refractive globules 

 and a thick (1.5-2 \i) smooth wall; functioning as prosporangia in 

 germination and giving rise to sporangia on their surface" (Karling, 

 loc. cit.). 



Saprophytic in fragments and exuviae of insects, from soil, Brazil. 



Rhizidium verrucosum Karling 



Amer. J. Bou, 31 : 255, figs. 34-63. 1944 



(Fig. 28 E-G, p. 440) 



"Thallus rarely wholly extramatrical. Sporangia extramatrical, non- 

 apophysate with a verrucose light or reddish brown, crusty outer wall 

 and a thinner hyaline inner wall; together up to 3.5 [i thick; spherical 

 (6-60 \i), oval (15 : 20-30 : 40 [i), oblong (20 X 35 \x), pyriform, or 

 egg-shaped; opening by a relatively large exit papilla which breaks 

 through the verrucose wall, exit orifice circular, oval or oblong, 7-10 u. 

 in diam. Rhizoidal system intramatrical, arising from one to three 

 points at base of sporangium, delicate or coarse, main axis up to 10 tx 

 in diam. and extending 300 [i in large thalli, becoming thick-walled and 

 brownish with age. Zoospores oval, 3-3.5 x 5-5.5 [i, with a relatively 

 small (1-1.5 u.) reddish-brown refractive globule lying slightly at one 

 side; emerging in a globular mass which becomes enveloped by a vesicle 

 in which the individuals swarm for several minutes before breaking out 

 and swimming away. Resting spores doubtful; dormant sporangia 

 spherical (8-22 (j.) or oval (6 x 12-9 x 16 u,), with brown warty thick 

 (4-6 [).) walls; functioning in germination directly as sporangia with an 

 exit papilla" (Karling, loc. cit.). 



Saprophytic on fragments and exuviae of insects, pieces of onion skin 

 and grass leaves, in water, Brazil. 



