CHYTRIDIALES 601 



Like Zygochytrium, which it closely resembles in its development, 

 thallus, and nonsexual reproduction, the species has never been ob- 

 served since its discovery by Sorokin and doubts as to its authenticity 

 have been freely expressed by mycologists. The blue coloration of the 

 protoplasm has without question added to this skepticism. Other water 

 fungi occurring on woody substrata occasionally show this bluish color 

 and specimens of Monoblepharis have been observed in which it has 

 been very pronounced (Sparrow, 1933b). This would not, however, ex- 

 plain the coloration presumably found also in Tetrachytrium growing 

 on the Coleoptera cadaver. 



Sorokin considered the "conjugation" of the zoospores (Fig. 38 J-L) 

 to form a zygote to be a very simple type of fertilization. A somewhat 

 similar occurrence was reported by Sparrow (1936a: 434) to take place 

 in Chytridium lagenaria, where, under poor conditions of nutrition, the 

 receptive thallus, after fusion of the contents of two encysted spores 

 (there was no merging of the bodies), underwent considerable vegeta- 

 tive development. In the Chytridium, however, it was un fused spores 

 rather than fused (as in Tetrachytrium) that were capable of germination. 



Further search will probably yield this fungus again and its true 

 relationships can then be established. 



ZYGOCHYTRIUM Sorokin 



Bot. Zeitung, 32: 308. 1874; Bull. Soc. Nat. Kazan, 4 (3): 12. 1874 

 (Fig. 38 A-E, p. 600; also, Fig. 4, R-T, p. 72) 



Zoospore upon germination forming at one pole a cylindrical axis 

 which branches dichotomously, at the opposite pole producing a broad 



and zoospores have a golden plasma with a vermilion globule. F-M. Tetra- 

 chytrium triceps Sorokin saprophytic on bits of wood: F, complete plant with 

 three sporangia and a recurved appendage; G, discharge of uncleaved proto- 

 plasm from sporangium; H, formation of four zoospores within vesicle at 

 orifice of sporangium; /, two of the four zoospores which have escaped at 

 rupture of vesicle; J-L, fusion of swarmers in pairs to form zygote; M, 

 germination of zygote to form new plant. Color of cytoplasm in Tetrachytrium 

 triceps is bluish. 



(After Sorokin, 1874a) 



