158. Vegetative cells 4-5/j. in diameter. Oe. trioicum 



158. Vegetative cells larger 159 



159. Oogonia oblong, 20-26^ in diameter, 41-60m long Oe. oblongum 



159. Oogonia suboblong-ellipsoid or fusiform, 24-30m in diameter, 

 48-62/tt long; wall of oogonium much thickened in the midregion 



( dioecious or monoecious ) Oe. inclusum 



160. Oogonia (49)-50-70^ in diameter 161 



160. Oogonia smaller 162 



161. Oogonia elUpsoid; oospores ellipsoid; vegetative 



cells smooth Oe. pachydermum 



161. Oogonia depressed-globose; oospores depressed-globose; 



vegetative cells spirally punctate Oe. spirostriatum 



162. Vegetative cells capitellate - Oe. bohemicum 



162. Vegetative cells not capitellate. - . 163 



163. Oogonia pyriform, 40--46m in diameter Oe. pyriforme 



163. Oogonia elUpsoid or obovoid-globose — 164 



164. Oospores ellipsoid, 53-62/ii long Oe. Ahhtrandii 



164. Oospores globose or subglobose, shorter — — 165 



165. Vegetative cells 10-16m in diameter Oe. crispum 



165. Vegetative cells 16-20^ in diameter ...Oe. autwnnale 



Section 1 

 Macrandrous — Dioecious — Poriferous 

 Oedogonium americanum Transeau 1917, p. 231 

 PL 43, Figs. 18, 19 

 Macrandrous; dioecious. Vegetative cells cylindrical, 28-48ju, in 

 diameter, 40-100^ long. Oogonia solitary; globose to depressed- 

 globose, or somewhat ellipsoid; opening by a superior pore; 40-76/a 

 in diameter, 48-70/x long. Oospores globose to ellipsoid-globose (or 

 depressed-globose); median wall scrobiculate; 38-74yLi in diameter, 

 46-56/x long. Antheridia 20-28/x in diameter, 4-12/x long. 

 Mich. 



Oedogonium amplum Magnus & Wille in Wille 1884, p. 40 



Macrandrous; dioecious. Vegetative cells (female) cylindrical, 

 46-54/A in diameter, 70-160;u, Iqng. Oogonia ovoid or ovoid-ellipsoid; 

 opening by a superior pore; 75-90)a in diameter, 83-115^ ^ong. 

 Oospores broadly ellipsoid to globose; wall smooth; 72-85/a in diam- 

 eter, 77-100/i, long. Antheridia 40-50/i, in diameter, 8-20/x long. 



Mich. 



Oedogonium angustum (Hirn) TiEany 1934, p. 324 



PI. 29, Figs. 1, 2 



Macrandrous; dioecious. Vegetative cells elongate-cylindric, (14)- 



19_30-(36)/.t in diameter, ( 57) -70-75- ( 330 )/.t long. Oogonia usually 



solitary (sometimes as many as 4 in a series); subovoid; opening 



by a superior pore; (40) -42-53^ in diameter, (62)-83-110/x long. 



[165] 



