Oospores oblong-ovoid; wall smooth; (40) -45-48- (53) /a in diameter, 

 (40)-57-70-(89)ja long. Antheridia 18-22/x in diameter, 7-10-(15)/. 

 long. 



Attached to submerged aquatics. Mich., Wis. 



Oedogonium anomalum Hirn 1900, p. 112 

 PI. 29, Figs. 3, 4 



Macrandrous; dioecious. Vegetative cells stout, cylindric; (37)- 

 40-50/x in diameter, 80-85- (300) /a long. Oogonia solitary; subovoid 

 or cylindric-ovoid; opening by a superior pore; (54)-56.3-64jli in 

 diameter, (68)-75-85/a long. Oospores globose or subglobose; not 

 filling the oogonia; wall of oospore smooth, thick; (48)-54-56-(60)ju, 

 in diameter, (52)-54-58-(61)/i, long; antheridia (not observed in 

 our specimens ) 30-40/a in diameter, 6-18)U. long. 



This plant should be compared with Oe. crassum, in which the 

 oogonium is ovoid or ellipsoid and in which the oospore more nearly 

 fills the oogonium. 



Mich., Wis. 



Oedogonium areolatum Lagerheim 1890, p. 80 

 PI. 31, Figs. 8, 9 



Macrandrous; dioecious. Vegetative cells cylindric, (16)-17-19- 

 (21)/i, in diameter, (59) -65-151- (165) /a long. Oogonia 1-4; obovoid 

 or somewhat globose; opening by a superior pore; 48-56-(60)/i, in 

 diameter, 60-70- ( 75 )iu. long. Oospores subellipsoid; nearly or quite 

 filling the oogonia; middle spore membrane coarsely areolate; (45)- 

 46-52- (57) /A in diameter, 48-56- ( 60 );u long. Antheridia 14-15/a in 

 diameter, 8-9- ( 10) /jl long. 



Attached to reeds and grasses. Mich., Wis. 



Oedogonium argenteum Hirn 1900, p. 289 

 PI. 31, Figs. 10, 11 



Macrandrous; dioecious. Vegetative cells cylindric, 14.2-23- ( 28 )/x 

 in diameter, ( 80 ) -107-133- ( 160 )/x long. Oogonia solitary; globose 

 or obovoid-globose; opening by a superior pore; 44-4^(52)/x in 

 diameter, ( 48) -62.9- ( 66.6 )/x long. Oospores globose or ovoid; not 

 filling the oogonia; outer spore wall deeply scrobiculate; (42.5)-43- 

 48/x in diameter, (44)-48-50|ii long. Antheridia 14-18-(22)^ in diam- 

 eter, 8-lOju, long. 



Attached to reeds in a gravel pit, and in a small pond. Mich., Wis. 



Oedogonium argenteum fa. michiganense TifFany 1930, p. 97 



PI. 43, Figs. 4, 5 

 Similar to the typical form except that the median spore wall is 

 scrobiculate; the pore supramedian. 



[166] 



