290 AQUATIC PHYCOMYCETES 



Parasitic on the planktonic green alga Gemellicystis neglecta, Great 

 Britain. 



"In its habit this fungus resembles Rhizophidiwn sphaerocystidis 

 Canter which likewise infects a planktonic alga surrounded by a wide 

 mucilage envelope. In both fungi the sporangium develops from the 

 encysted zoospore while the germ-tube remains as a stalklike portion. 

 However, in the method of dehiscence and in resting-spore formation 

 these fungi differ greatly" (Canter, op. cit., p. 144). 



Rhizophydium parasiticum Shen and Siang 



Science Reports of National Tsing Hua University, Ser. B: Biol, and Psych. 



Sciences, 3: 181, fig. 2. 1948 



"Zoosporangia, epibiotic, obpyriform, 20-22 u, long, 18-20[a wide, 

 wall 1-1.5 (x thick, opening by a lateral pore, 5.4 u. in diameter, allow- 

 ing the fully formed zoospores to ooze out in the form of a sporal globe; 

 rhizoids beneath the sporangium very delicate, hardly visible; zoo- 

 spores spherical, posteriorly uniflagellate, 5.4 \x in diameter, containing 

 a well defined refractive body, about 3.3 \x in diameter; emptied zoo- 

 sporangia persistent; resting spores unknown" (Shen and Siang, he. 

 cit.). 



Parasitic in the zygote of Oedogonium sp., China. 



From the figures, the sporangium appears to have a short, solid 

 pedicel. 



Rhizophydium echinatum (Dang.) Fischer 



Rabenhorst. Kryptogamen-Fl., 1 (4): 96. 1892 



C/n iridium echinatum Dangeard, Journ. de Botanique, 2: 143, pi. 5, figs. 

 11-15. 1888. 



Sporangium sessile, very broadly obpyriform with a strongly ob- 

 tuse somewhat lobed apex, urceolate at maturity, 13.5 [jl high by 10.8 u. 

 in diameter (at apex?), wall thin, smooth, colorless; rhizoidal system 

 consisting of an unbranched short tapering stalk; zoospores spherical, 

 2.5 [i in diameter, with a basal colorless globule and a long flagellum, 

 emerging through a very broad apical opening with a reflexed rim 

 and forming a compact temporary mass surrounded by mucus; resting 



