This plant should be compared with Oe. crassum and Oe. 

 martinicense Hirn. From the latter, which is monoecious, it is easily 

 distinguishable if favorable material is at hand. 



In kettlehole pond. Mich., Wis. 



Oedogonium lautumniarum Wittrock in Wittrock & 

 Nordstedt 1877, Algae Exsic. No. 7, p. 22 



Macrandrous; dioecious. Vegetative cells cylindric, 16-22jli in 

 diameter, 40-1 10/x long. Oogonia solitary (sometimes 2); subovoid- 

 globose; opening by a supramedian or sometimes nearly superior 

 pore; 40-49|U, in diameter, 45-51/x long. Oospores subglobose 

 ( subangular-globose ) ; filling the oogonia; wall smooth; 36-46/i, in 

 diameter, 35-47/* long. Antheridia 14-17/a in diameter, 7-10/i, long. 



Mich. 



Oedogonium longiarticulatwn ( Hansg. ) Tiffany 1934, p. 325 



Macrandrous; dioecious. Vegetative cells cylindric, 12-15/i in 

 diameter, 60-90/x long. Oogonia solitary; obovoid to subellipsoid; 

 opening by a superior pore; 27-32/a in diameter, 58-60/i long. 

 Oospores obovoid to ellipsoid; outer wall smooth; median wall with 

 12-18 longitudinal, crenate costae; 24-30/a in diameter, 44-52/* 

 long. Antheridia 8-1 l/i in diameter, lO-15/i long. 



Mich. 



Oedogonium Magnusii Wittrock 1875, p. 38 



Macrandrous; dioecious. Vegetative cells cylindric, elongate; 7-10/* 

 in diameter, 12-40/* long. Oogonia 1-3; depressed-globose; opening 

 by a median pore; 24-27/* in diameter, 21-26/i long. Oospores 

 depressed-globose and filling the oogonia; the outer wall smooth, 

 the median wall coarsely scrobiculate; 22-25/i in diameter, 18-23/* 

 long. Antheridia 8-10/* in diameter, 5-11/* long. 



Mich. 



Oedogonium majus ( Hansg. ) Tiffany 1934, p. 324 



Macrandrous; dioecious. Vegetative cells cylindric, 36-46/* in 

 diameter, 80-200/t long. Oogonia 1-3; subobovoid to nearly ellipsoid; 

 opening by a superior pore; 52-58/* in diameter, 75-90/i long. 

 Oospores subobovoid, filling the oogonia; wall smooth; 50-64/* in 

 diameter, 68-88/* long. Antheridia 30-36/* in diameter, 10-16/* long. 



Mich. 



Oedogonium mexicanum Wittrock 1878, p. 138 



Macrandrous; dioecious. Vegetative cells cylindric, 34-41/* in 

 diameter, 60-140/i long. Oogonia cylindric-ovoid; opening by a 

 superior pore; 53-63/* in diameter, 76-110/* long. Oospores cylindric- 



[172] 



