CHYTRIDIALES 515 



On Oedogonium sp., Schenk (be. cit.), no specific substratum, Minden 

 (1915: 340), Germany; Closterium sp., Cejp (1933a: 5, pi. 1, fig. 12), 

 Czechoslovakia; Bulbochaete sp., Spirogyra sp., Zygnema sp., Closte- 

 rium sp., Cladophora sp., Oedogonium sp., Dangeard (be. cit.), Spirogyra, 

 de Wildeman ( 1 894 : 1 55), France ; Oedogonium sp., de Wildeman ( 1 895a : 

 72, pi. 2, figs. 13-16), Switzerland; Oedogonium sp., Cladophora sp., de 

 Wildeman (1890: 6, fig. 1), Belgium; oogonia, oospores, vegetative cells 

 of Oedogonium sp., Scherffel (be. cit.; 1914), Oedogonium sp., Spirogyra 

 sp., Domjan (1936: 49, pi. 1, figs. 42-43, 60-61), Hungary; Oedogonium 

 sp., Bulbochaete sp., Spirogyra sp., Closterium sp., Petersen (1909: 416, 

 fig. 22g ; 1 9 1 : 550, fig. 22g), Denmark ; Oedogonium sp., Sparrow ( 1 932b : 

 280, fig. 3 a-d; 1933a: 67, fig. lq), vegetative filaments of Oedogonium sp., 

 Sparrow (1952d: 768), United States; Cladophora, Closterium, Litvi- 

 now (as Phlyctochytrium sehenkii), (1953: 81), Latvia. 



In its present form Chytridium sehenkii is probably a composite 

 species made up of several varieties, some of which have been published 

 as distinct entities. Thus C. gibbosum Scherffel and C. aggregatum 

 Karling have been suggested by their authors to be only doubtfully 

 distinct from it. They are, however, maintained separate in the present 

 monograph. Some of the records of occurrence listed above are, from 

 examination of the figures, to be accepted with reservations. It is remark- 

 able that of the many reports of this fungus only one of the descriptions 

 includes any measurements of the sporangium and apophysis; significant 

 variations in the size of these structures, consequently, cannct be given. 



The British fungus discussed as Chytridium sehenkii (Sparrow, 1936a: 

 431) seems closer to C. scherffelii Sparrow. 



Scherffel first emphasized the fact (noted by Schenk) that the sporan- 

 gium developed by lateral and upward expansion of a portion of the 

 body of the infecting zoospore and that the remainder persisted as a 

 distinct protuberance on the sporangium wall. He also pointed out that 

 similar protuberances are found on Schenk's and Dangeard's fungi. 



It is not unlikely that an inoperculate form with this type of develop- 

 ment and similarly shaped sporangia may be found, in which event 

 doubt will be thrown on the advisability of considering Dangeard's 

 form (in which no operculum was observed) identical with Chytridium 

 sehenkii. 



