CHYTRIDIALES 221 



or discoid base which extends into the host cell. Spores emerging 

 through an apical pore. Spores not seen. Resting spores not seen" 

 (Couch, he. cit.). 



Parasitic on Bumilleria sp., United States; ? Zygnema sp., Berczi 

 (1940: 80, pi. 2, fig. 7-10), Hungary. 



The fungus attacked the healthy cells of the alga and destroyed 

 them. Couch considered the species close to Phlyctidium chlorogonii. 



Phlyctidium brevipes var. brevipes (Atkinson) Minden 

 Kryptogamenfl. Mark Brandenburg, 5: 313. 1911 (1915) 

 Rhizophydium brevipes Atkinson, Bot. Gaz., 48: 322, fig. 2. 1909. 



Sporangium sessile, ovoid or spherical, 10.2-24 \x in diameter, with 

 a protruding apical papilla, wall smooth, colorless, double-contoured; 

 haustorium consisting of a short, blunt peglike tube which projects 

 only slightly beyond the inner face of the algal wall; zoospores ovoid, 

 about 3 \jl in diameter, with a colorless globule and flagellum, escaping 

 through an apical pore about 4 [j. in diameter formed upon the deli- 

 quescence of the papilla; resting spore not observed. 



On gametangia of Spirogyra various, Atkinson (loe. cit.), United 

 States; vegetative cells of Oedogonium sp., Spirogyra sp., Tokunaga 

 (1934b: 388, pi. 11, figs. 1-2), Japan. 



Atkinson observed that several zoospores which at maturity were 

 unable to escape formed long germ tubes that penetrated the wall 

 of the sporangium. Not having reached a suitable substratum by this 

 means, they quitted their cysts, swarmed again, came to rest, and once 

 more penetrated the sporangium wall with their germ tubes. Atkinson 

 saw in the production of this long germ tube a method whereby the 

 zoospore might without swimming be able eventually to reach a favor- 

 able substratum. 



Phlyctidium brevipes var. marinum Kobayasi and Ookubo 



Bull. Nat. Sci. Mus. (Tokyo), (N.S.) 1 (2) (35): 62, fig. 1. 1954 



"Zoosporangium solitary, epibiotic, sessile, globose, subglobose or 

 ovoid, 25-34 \l high, 20-30 [x in diameter (commonly 34 x 30 \l), hya- 

 line, smooth, somewhat thick-walled (2-3 \i thick), with a broad apical 



