diameter, (60) -80-96/1, long. Oospores ellipsoid; nearly filling the 

 oogonia; wall of two layers, the outer with 13-15 longitudinal ribs 

 with smooth edges; 44.5/x in diameter, 66.6/* long. Antheridia 14.8ju, 

 in diameter, T.Syn long. Suffultory cell 27.7/a in diameter, 65-85// long. 

 Attached to submerged aquatics in shallow water. Wis. 



Oedogonium giganteum Kuetzing 1845, p. 200 

 PL 30, Figs. 3, 4 



Macrandrous; dioecious (male plants not observed in our collec- 

 tions). Vegetative cells cylindrical, (30) -46-48- (50) /a in diameter, 

 65-200- ( 225 )/i, long. Oogonia solitary; cylindric-obovoid or ellipsoid; 

 opening by a superior pore; (53)-55-60-(69)ja in diameter, 65-95- 

 (106)/x, long. Oospores ellipsoid; nearly filling the oogonium; wall 

 of three layers, the middle layer with longitudinal rows of deep pits; 

 ( 51 )-55-65/x in diameter, 90-93- ( 103 )/x long. 



In shallow swamp. Wis. 



Oedogonium gracilius ( Wittr. ) Tiffany 1934, p. 324 

 PL 29, Figs. 12-14 

 Macrandrous; dioecious. Vegetative cells cylindric, 20-25/x in 

 diameter, (40)-51-100yu, long. Oogonia solitary; obovoid-globose; 

 opening by a superior pore; 36-42/a in diameter, 44.4-46-(57)/i, long. 

 Oospores globose; nearly filling the oogonia; wall smooth; 33-35- 

 (39)/u, in diameter, 33-35- ( 44 )ju, long. Antheridia (not observed in 

 our collections ) 19-22/a in diameter, 7-lOyu, long. 



Attached to grass in several shallow water habitats. Mich., Wis. 



Oedogonium grande Kuetzing 1845, p. 200 

 PL 29, Figs. 15-17 



Macrandrous; dioecious. Vegetative cells cylindric, ( 28) -33-37- 

 {40)ix in diameter, (70)-122-159-(210)/x long. Holdfast cell elongate. 

 Oogonia 1-5; ellipsoid or subovoid; opening by a superior pore; 

 (49) -59.2-60/* in diameter, (74)-86-110/u. long. Oospores the same 

 shape as the oogonia, which they completely fill; wall smooth; 

 (47)_52-58/t in diameter, (60) -70-80- (94)/. long. Antheridia (not 

 observed in our collections) 25-33// in diameter, 11-18/t long. 



Attached to submerged grass and leaves in swampy end of a 

 lake. Wis.; also Mich. 



Oedogonium grande var. aequatoriale Wittrock in Wittrock & 



Nordstedt 1893, Algae Exsic. No. 1016 



PL 29, Fig. 18 



Macrandrous; dioecious. Vegetative cells cylindric, (22)— 24— 26 

 -(33) /I in diameter, ( 70 ) -88-90- ( 165) /t long. Oogonia 1-5; ob- 



[170] 



