which can be identified when in the vegetative condition, because 

 of the distinctive cell shape. 



Common in many desmid habitats where the water is soft or 

 acid. Mich., Wis. 



Oedogonium spheroideum Prescott 1944, p. 353 

 PI. 38, Figs. 3, 4 



Macrandrous; monoecious. Vegetative cells elongate-cylindric, 

 16-19;u in diameter, 115-155/x long. Oogonia solitary; broadly ellip- 

 soid to subglobose; operculate; division superior; 55-64/x in diameter, 

 80-87.5/i. long. Oospores spheroidal, the wall thick; outer membrane 

 with 12-15 longitudinal ribs; 57-60;u, in diameter, 57-60/x long. 

 Antheridia 1-4, immediately below the oogonia or scattered. Anther- 

 ozoids 2; the division horizontal; 19-21/x in diameter, 16//, long. 



This species should be compared with Oe. sol Hirn, which is 

 smaller and has an oospore with the middle, rather than the outer, 

 layer of the wall ribbed. 



Attached to grass in a roadside swamp. Wis. 



Oedogonium spirostriatum Tiffany 1936a, p. 2 

 PI. 44, Figs. 1, 2 



Macrandrous; monoecious. Vegetative cells slightly capitellate; 

 16-24-(28)/x in diameter, 50-164^ long; wall of the vegetative cells, 

 as well as of oogonia, with spirally disposed punctations; basal cell 

 hemispherical to nearly globose. Oogonia solitary; subglobose to 

 depressed-globose; operculate; division supramedian; 49-56/i, in 

 diameter, 40-50;u, long. Oospores depressed-globose; about the same 

 shape as the oogonia but not filling them; 40-47/^ in diameter, 

 34-40/x long. Antheridia 20-24/x in diameter, 17-20^ long. 



This species should be compared with Oe. punctatostriatum, 

 which is dioecious and has cylindric cells; also the oogonium of Oe. 

 punctatostriatum has a median, rather than a supramedian, division. 



Common in many lakes. Mich., Wis. 



Oedogonium spurium Hirn 1900, p. 301 



Macrandrous; monoecious or dioecious. Described in previous 

 section. 



Oedogonium trioicum Woronichin 1923, p. 99; 1923a, p. 141 



Macrandrous; monoecious or dioecious. Described in previous 

 section. 



[194] 



