This species should be compared with Oe. Hotvardii, which also 

 has capitellate cells. In that form, however, the oogonia average 

 larger and the basal cell is subhemispherical or nearly spherical. 

 Our specimens of Oe. calvum usually showed oogonia in series of 4. 



Entangled about grass in a roadside pool. Wis. 



Oedogonium epiphyticum Transeau & Tiffany in Tiffany 1934, p. 325 



PI. 36, Figs. 20, 21 



Macrandrous; dioecious. Vegetative cells cyhndric, (6)-7.4— 8-(9)ju, 

 in diameter, 15-25- ( 45 )/x long; basal cell elongate. Oogonia solitary 

 or (rarelv) as many as 3 in a series; ellipsoid or ellipsoid-ovate; 

 operculate; division superior; (16)-17-18-(20)/i, in diameter, (20) - 

 26- (30)//. long. Oospores elliptical; nearly filling the oogonia; wall 

 smooth; 14.8-16-(18)/t in diameter, 16-l9-{28) fi long. Antheridia 

 5-6 fx in diameter, (5)-8-10/x long. 



Entangled about grass in a roadside pond. Wis. 



Oedogonium Hotvardii G. S. West 1904a, p. 281 



Macrandrous; dioecious. Vegetative cells capitellate; elongate, 

 8-10- (12) IX in diameter, (18)-20-40-(42)/^ long. Oogonia solitary 

 or 2 together; globose; operculate; division median; (25)-28-29-(33)|u, 

 in diameter, (26)-30-34/a long. Oospores globose; wall smooth; 

 22-26- ( 30 )/t in diameter. Antheridia (7)-10-12.5/a in diameter, 

 (10)-12-14/ilong. 



Floating clots of filaments. Wis. 



Oedogonium inclusum Hirn 1895, p. 2 

 PI. 35, Figs. 5-7 



Macrandrous; dioecious (?). Vegetative cells cylindric or some- 

 what capitellate, (8)-12.9/x in diameter, (33)-62.9-150/a long. 

 Oogonia solitary; oblong-ellipsoid or fusiform, with lateral walls 

 much thickened; operculate (?), opening superior; 24-30/a in 

 diameter, 48-55- (62) /a long. Oospores ellipsoid; filling the oogonia 

 laterally; wall smooth; (18)-24-(30)/i in diameter, 38-45- (48)/. 

 long. Antheridia not observed. 



Attached to overhanging grass in Sphagnum bog ditches. Wis. 



Oedogonium inconspicuum Hirn 1895, p. 23 



PL 37, Figs. 1, 2 



Macrandrous; dioecious. Vegetative cells cylindric; sometimes 



twisted and swollen irregularly; 3.7-5/i in diameter, 17.8-25- ( 35 ))ii 



long. Oogonia solitary; globose or pyriform-globose; operculate; 



[183] 



