[50 AQUATIC PHYCOMYCETES 



w Inch projects slightly through the wall of the host; zoospores rounded, 

 possibl) with only a single flagellum; resting spore not observed. 



Parasitic in Chlorodeiulron subsalsum, France. 



A subsequent (1955) paper by J. and G. Feldmann presents mor- 

 phological data supporting their combination. See page 811. 



/// Fresh-Water Algae 



? Olpidium algarum Sorokin 

 Arch. Bot. Nord France, 2: 30, fig. 32. 1883 (separate) l 

 Olpidium algarum var. longirostrum Sorokin, loc. cit. 



Sporangium narrowly ellipsoidal, wall thin, smooth, colorless, resting 

 with its long axis parallel with that of the algal cell, forming at one 

 end a long, moderately broad, somewhat curving discharge tube with 

 a funnel-like apex, which extends slightly beyond the outer wall of 

 the alga; all other characters unknown. 



On "Confervacees" (Tribonema ?), Asiatic Russia. 



There is no Olpidium algarum of which two varieties, longirostrum 

 and brevirostrum, have been described, and the former has therefore 

 been taken as the type. 



From the illustration given, the alga appears to be a Tribonema- 

 like form. The cross wall shown between the parts of the two cells 

 figured has apparently been stimulated to protective-plug formation, 

 probably by another fungus. The sporangia have been calculated from 

 the figures to be about 6 \x high by 12 u. wide, the tube about 12 \x long. 



The species is not considered distinct from Olpidium entophytum 

 by Fischer (1892:25) and Minden (1915:243). 



De Wildeman (1893b: 49, pi. 7, fig. 4), using the name Olpidium 

 algarum Sorokin, describes a form in Desmidium swartzii from Bel- 

 gium which resembles Sorokin's var. brevirostrum in the shape of its 

 sporangium, but which possesses a somewhat longer discharge tube. 

 I k suggests that the length of the tube depends on the size of the host 

 cell. and. while he would conseiwe the name O. algarum, his form would 

 he intermediate between the two varieties. 



Sec also Sorokin. Revue Mycologique, li: 84, pi. 80, fig. 96. 1889. 



