opening by a superior pore; 30-36/a in diameter, 40-61- ( 65 )/i, long. 

 Oospores ellipsoid; not filling the oogonia; median spore wall with 

 about 20 longitudinal ribs with crenulate edges; 27— 35/t in diameter, 

 40-65/A long. Antheridia 10-12ju in diameter, 13-14/x long. 



Rather common, mostly in small ponds and roadside swamps. 

 Mich., Wis. 



Oedogonium crenulatocostatum var. cylindricum 



(Hirn) Tiffany 1937, p. 42 



PI. 30, Figs. 13-15 



Similar to the typical plant, but with oogonia and oospores 



distinctly cylindric-oblong, and with the costae of the oospore wall 



nearly entire or smooth. Oogonia 30-35/^ in diameter, 42-78-(81)/i 



long; oospores 27-30-(34)/x in diameter, (42)-52-62/a long. 



Attached to submerged aquatics with several other species of 

 Oedogonium. Wis. 



Oedogonium crenulatocostatum var. cylindricum fa. major 



Prescott 1944, p. 352 

 A form larger than the typical. Vegetative cells 25.9^ in diam- 

 eter, 88.8/A long. Oogonia 1-3; obovoid-ellipsoid or cylindric-oblong; 

 opening by a superior pore; 42.5-44/a in diameter, 63-74/i, long. 

 Oospores ovoid-ellipsoid; wall thick; middle layer with about 16 

 longitudinal ribs which are quite smooth (not crenulate); 37-39/a 

 in diameter, 55.5-57/x, long. 



Floating in backwater of small lakes. Wis. 



Oedogonium diversum ( Hirn ) Tiffany 1934, p. 324 

 PI. 29, Figs. 9-11 



Macrandrous; dioecious. Vegetative cells stout, cylindric; 40- 

 (43)_44.4_(46)^ in diameter, ( 45) -56-92- ( 130 )/a long. Oogonia soli- 

 tary; obovoid; opening by a superior pore; (43) -55-56- (62) /a in 

 diameter, (46)-66-70ju, long. Oospores globose or subglobose; not 

 filling the oogonia; wall thick, smooth; (43) -45-55. 5/a in diameter, 

 (40)-55.5-(58)/x long. Cells of male filament 33.3-37-(40)/a in 

 diameter, ( 50) -56-92- ( 120 )/z long. Antheridia 2-5, 33-37/x in diam- 

 eter, 6/x long. 



Pooled seeps. Wis. 



Oedogonium exocostatum Tiffany 1921, p. 272 



PL 30, Figs. 11, 12 



Macrandrous; dioecious. Vegetative cells cylindric, 12.9-22.2~(25)/i, 



in diameter, (72) -85-92- (140)^ long. Oogonia l-2-(3); ellipsoid 



or ellipsoid-globose; opening by a superior pore; 40-50- ( 52 )/x in 



[169] 



