CHYTRIDIALES 349 



Phlyctochytrium unispinum Paterson 

 Mycologia, 48: 270, fig. 1 a-i. 1956 



"Sporangium sessile, the wall in part formed by the separation of the 

 zoospore cyst, each half of which remains an unmodified hemispherical 

 projection, giving the whole a somewhat irregular ellipsoid appearance, 

 12.5-17.5 \x from one portion of the zoospore cyst wall to the opposite 

 wall, bearing at maturity a single apical spine, 3.5-6.5 jx long; endo- 

 biotic system a spherical apophysis 7-21 (j. in diameter with a single 

 isodiametric rhizoid, 0.5-1 \x wide; zoospores spherical, 6-7.5 [i in 

 diameter, with a single eccentric oil globule surrounded by granular 

 protoplasm, discharged into the basal portion of the spine which swells 

 into a vesicle, liberated upon the dissolution of the vesicle, leaving the 

 terminal part of the spine undissolved and free in the medium; resting 

 spore not observed" (Paterson, he. cit.). 



Saprophytic on Oedogonium sp., Zygnema sp., and Stigonema sp., 

 United States. 



The type of sporangial development, involving separation and re- 

 tention of the rigid wall of the encysted zoospore, is unique. 



Phlyctochytrium variabile Rieth 

 Die Kulturpflanze, 2: 180, fig. 9. 1954 



Sporangium subspherical, bowl-like, bearing on the broadly arched 

 apex variable numbers of four-parted teeth and on the rim a crown 

 of solid two-pronged teeth, (6)— 1 0— ( 1 2) \x high (including teeth) by 

 (5)-9-13-(17) [x in diameter; endobiotic part with one, rarely two sub- 

 sporangial apophyses and branched rhizoids; zoospores nearly spherical, 

 2.6-3.6 (jl in diameter with a refractive droplet; resting spore not observ- 

 ed. 



Saprophytic on Spirogyra sp., Germany. 



Close to Phlyctochytrium mucronatum Canter and P. aureliae Ajello. 



Phlyctochytrium vaucheriae Rieth 

 Die Kulturpflanze, 4: 185, fig. 1, pi. 6. 1956 



Sporangium epibiotic, sessile, highly variable in size and shape, 

 typically somewhat saccate, with one or two broad uptilted discharge 



