CHYTRIDIALES 217 



in diameter which bears a series of tenuous radiating hairs on the 

 outer surface. The haustorium consists of a stout somewhat irregular 

 unbranched filament 40 \x long by 8 \x in diameter and slightly expanded 

 at the point of contact of the inner wall of the alga. No zoospore 

 discharge was seen. Except for the haustorium the organism resembles 

 an immature specimen of Phlyctochytrium chaetiferum. 



Phlyctidium anatropum (Braun) Rabenhorst 



Flora Europaea algarum, 3: 279. 1868 



(Fig. 19 A-B, p. 318) 



Chy Iridium anatropum Braun, Flora (N.S.), 14: 599. 1856; Monatsber. 

 Berlin Akad., 1856: 588. 



Sporangium sessile, procumbent or upright, irregular, broadly pyri- 

 form, ovoid, asymmetrical, strongly arched or reflexed (anatropous), 

 rarely symmetrical, attached laterally near the narrower end to the 

 algal cell, 5-14 jx wide by 15-33 [x (rarely 50 ;x) long, wall thin, smooth, 

 colorless; haustorium very small, rounded or short-peglike ; zoospores 

 elongate, 5 jx long by 2 \i wide, with a minute, inconspicuous globule 

 and flagellum, discharged through a single pore (rarely two) formed 

 at either of the apices and remaining in a loose cluster at the orifice 

 before creeping away, movement strongly amoeboid, the body forming 

 pronounced pseudopodia, swimming motion not observed; resting 

 spore spherical or ovoid, with a smooth thick faintly brownish wall, 

 10 jx in diameter, contents with globules, haustorium like that of the 

 sporangium, germination not observed. 



Parasitic on Chaetophora elegans, Braun (be. cit.), Oscillatoria sp., 

 Schenk (1858b: 8), Germany; Stigeoclonium sp., Sparrow (1933c: 516, 

 pi. 49, figs. 4-8), Couch (1935a: 170, figs. 56-63), United States; 

 Tribonema sp., Berczi (1940: 80, pi. 2, figs. 5, 6), Hungary. 



Phlyctidium mycetophagum Karling 



Amer. J. Bot., 33: 756, figs. 44-55. 1946 



"Sporangia hyaline, smooth predominantly obpyriform (8-30 jx high 

 by 10-25 [x in greatest diameter) with a tapering or slightly in- 

 flated base, occasionally almost spherical or oval, with 1-4 low, in 



