222 AQUATIC PHYCOMYCETES 



or subapical papilla. Rhizoid (haustorium) simple, short, thick and 

 peglike, projecting only slightly beyond the inner face of the hostwall. 

 Zoospores emerging one by one through a pore after the deliquescence 

 of the papilla, globose, about 4-5 u, in diameter, with a globule and 

 a 1 5 (x long posterior flagellum. Resting spore not observed" (Kobayasi 

 and Ookubo, he. cit.). 



On Bryopsis sp., Japan. 



Differing slightly from Phlyctidium brevipes in its somewhat larger 

 sporangia and zoospores and in its marine habitat. 



Phlyctidium piriformis (Fott), comb. nov. 



Hapa/opera piriformis Fott, Studia Bot. Cechica, 5 (3-4): 170, pi. 19, 

 figs. 1-5. 1942. 



Sporangium obpyriform or lacrimoid, on a very short or a long 

 slender stalk, wall delicate, 24 jx long; rhizoid a fine thread; zoospores 

 spherical, 2-3 u, in diameter, with a single oil droplet and 13-15 jx 

 long flagellum, liberated upon the deliquescence of the entire sporan- 

 gium wall: resting spore not observed. 



Parasitic on Characium ancora, Czechoslovakia. 



Since partial or nearly complete deliquescence of the sporangium 

 wall occurs in other chytrids, this character alone is not of generic 

 significance. Because it is soon lost in the host contents, whether or 

 not the rhizoid is unbranched is not certain. 



Phlyctidium tenue Sparrow 

 Mycologia, 44: 760, fig. 1 a-g. 1952 



Sporangium sessile, somewhat hemispherical, 15-16 tx in diameter 

 by 12-14 fx high; wall smooth, colorless, distinctly thickened on the 

 lower part of the sporangium so as to form a cuplike base; haustorium 

 slender, double-contoured, usually straight, unbranched, isodiametric, 

 of variable length; zoospores numerous, oblong, 5 ;x long by 2.5 u, 

 wide, with a centric, colorless refractive globule and a single posterior 

 flagellum 15 u, long, escaping through a single apical pore after which 

 the sporangium wall collapses; resting spores epibiotic, sessile, spheri- 

 cal, and 13-15 (x in diameter, or ellipsoidal and 10 by 12 |x, with a 



