CHYTRIDIALES 389 



doubts as to its affinities with Nephrochytrium were expressed by its 

 author. 



Diplophlyctis sexualis Haskins 



Mycologia, 42: 775, figs. 1-10. 1950 



"Asexual thallus monocentric, usually intramatrical, consisting of a 

 sporangium or resting spore subtended by an apophysis from which 

 arises a somewhat coarse, branched rhizoidal system. Sporangia hyaline, 

 smooth, spherical, 50-170 \x in diameter, or variously shaped, walls 

 not staining with zinc chloroiodide. Exit tubes one to several, short 

 and broad, or occasionally very long up to 1 50 [jl. Dehiscence by deli- 

 quescence of tips of exit-tubes or by tip of tube softening to form an 

 evanescent gelatinous plug beneath which an "endo-operculum" may 

 or may not develop. Endo-opercula, when formed, shallow saucer- 

 shaped, to cone-shaped with long spine. Zoospores spherical to sub- 

 spherical, 5-6 [i. in diameter each with single, large, prominent, highly 

 refractive globule and a 30-40 ;x flagellum, remaining temporarily 

 motionless immediately after discharge, intermittently amoeboid. A- 

 pophysis spherical or variously shaped, joined to sporangium by a wide 

 isthmus. Sporangium and apophysis originating at the same time at 

 the end of an usually short branch of the germination tube from the 

 encysted zoospore. Rhizoidal system usually arising from basal half 

 of apophysis, stout, extensive, and much branched. Resting spores 

 spherical, 16-23 \l in diameter; contents coarsely globular; wall thick, 

 layered, dark brown, densely spiny, spines short and stout to long and 

 hair-like; formed asexually or only after sexual fusion. Female thalli 

 as for resting spores and remaining abortive unless fertilized. Mala 

 thalli consisting of a gametangium, apophysis and rudimentary sparsely- 

 branched rhizoidal system. Gametangium hyaline, thin-walled con- 

 taining 4 to many gametes. Gametes encysting in situ producing fine 

 sparsely-branched rhizoid-like germination tubes which penetrate 

 gametangium wall to anastomose with rhizoidal system of female 

 thallus, through which anastomosis the content of the male cell passes 

 to enter the female cell, which immediately develops into normal, brown, 

 spiny-walled resting spore. Resting spores functioning as pro-sporangia 



