CHYTRIDIALES 341 



Phlyctochytrium planicorne Atkinson 



Bot. Gaz., 48: 337, fig. 7. 1909 



(Fig. 191, p. 318) 



Sporangium sessile, occasionally stalked, broadly ellipsoidal, nar- 

 rowly to broadly ovoid, or narrowly pyriform, variable in size, 6-24 [i 

 high by 6-17 u, in diameter, wall thin, colorless, smooth, bearing at 

 the apex and around the discharge papilla a collarette of four (rarely 

 six) solid highly refractive slightly converging plain teeth rarely more 

 than 4(jl high; rhizoidal system extremely variable in its development, 

 consisting of a few short branches or an extensive much-branched 

 complex, in either type arising from a fusiform to spherical subspo- 

 rangial apophysis 3-13 \x in diameter when spherical, when subspheri- 

 cal up to 12 jx in diameter by 10 ;x high; zoospores spherical, 3-6 u, 

 in diameter, with a prominent eccentric colorless globule about 3 \x 

 in diameter and a few minute droplets in the plasma, flagellum about 

 30 [i long, emerging individually through an apical pore and eventually 

 swimming away, or discharged in a compact group possibly sur- 

 rounded by an evanescent vesicle, movement swimming or amoeboid; 

 resting spore not observed. 



Parasitic on Spirogyra various, Atkinson (he. cit.), Rhizoclonium 

 hieroglyphicum, Spirogyra sp., Sparrow (1932b: 279, fig. 3 e-k), sap- 

 rophytic on Cladophora sp., Oedogonium sp., Sparrow (1938c: 486, 

 figs. 1-6), saprophytic in decaying stems of Acorns calamus, Sparrow 

 (1943: 230), oogonia of Oedogonium sp., Sparrow (1952d: 765), United 

 States; Vaucheria sp., Berczi (1940: 83, pi. 2, figs. 21-22), Hungary. 



Phlyctochytrium zygnematis (Rosen) Schroeter 



Engler and Prantl, Natiirlichen Pflanzenfam., 1 (1): 79. 1892 



Chytridium zygnematis Rosen, in Cohn, Beitr. Biol. Pflanzen, 4: 266, pi. 13, 



figs. 1-14, pi. 14, figs. 15-27. 1887. 

 R/iizidiuni zygnematis (Rosen) Dangeard, Le Botaniste, 1 : 64. 1889. 



Sporangium sessile or occasionally stalked, spherical or broadly 

 ovoid, about 15-17 [jl in diameter, with an apical collarette of four 

 somewhat elevated, upright, solid, shallowly bipartite teeth which 

 surround the discharge papilla; rhizoids well developed, branched, 



