CHYTRIDIALES 439 



Parasitic on diatoms, coll. P. W. Richards, Sarawak. 



In the shape of its sporangium this fungus closely resembles Rhizo- 

 phlyctis mastigotrichis (Nowak.) Fischer. It has, however, much smaller 

 sporangia (12-15 by 7-10 \x as compared to ones 40 \x in diameter), the 

 rhizoids are more delicate and attenuated, not swollen distally, and a 

 smaller number of zoospores (from four to six rather than fifty or more) 

 are produced in each sporangium. 



Rhizophlyctis mastigotrichis (Nowak.) Fischer 

 Rabenhorst. Kryptogamen-FL, 1 (4): 121. 1892 



Chytridium mastigotrichis Nowakowski, in Cohn, Beitr. Biol. Pflanzen, 



2:83, pi. 4, figs. 14-21. 1876. 



Sporangium resting directly on or between the host filaments, spher- 

 ical or somewhat ellipsoidal, about 40 \x in diameter, the apex prolonged 

 into a short beak or a long tube, wall colorless, thin, smooth except in 

 the apical region, where toothlike or small knoblike elevations may be 

 present; rhizoids occasionally lacking, frequently from one to two, 

 sometimes numerous, arising from the lower part of the rudiment of 

 the sporangium, branched or unbranched, tapering or the tips expanding 

 into a somewhat spherical haustorial structure where they make contact 

 with the host cell; zoospores large, 8 \x long by 5 (j. in diameter, ovoid 

 with a blunt rounded anterior end, possessing a large narrowly ovoid 

 strongly refractive globule, granular near the base and with a lateral 

 extremely refractive elongate granule, flagellum attached at the narrower 

 end, emerging from the tip of the discharge tube and forming a spherical 

 motionless mass surrounded by an evanescent envelope of slime, move- 

 ment somewhat slow in a straight or zigzag curving line, also amoeboid; 

 resting spore not observed. 



Parasitic on Mastigothrix (Calothrix) aeruginea, Germany; from soil, 

 substrate ?, Gaertner (1954b: 22), South Africa. 



Rhizophlyctis tolypotrichis Zukal 



Osterr. botan. Zeitschr., 43: 310, pi. 11, fig. 13. 1893 



Sporangium resting loosely on or occasionally within the swollen 

 sheath of the alga, subspherical, sometimes slightly angular, with a 



