OED OGONELUM~ ; 69 
10. Oe. varians Wittrock and Lundell. 
(Pl. XII, fig. 120.) 
In Wittr. 1874, p. 11; Oe. polymorphum Wolle 1887, p. 73, Pl. LXXIV, figs. 
16-19; Hirn 1900, p. 89, Pl. IV, fig. 23; Collins 1909, p. 232; Heering 1914, p. 206, 
fig. 298; Tiffany 1926, p. 99, Pl. VII, figs. 75 and 76. 
Monoecious, (or sometimes dioecious); oogonium 1, or rarely more, 
depressed- or subdepressed-pyriform-globose, pore nearly superior; 
oospore globose, not filling oogonium, spore wall smooth; antheridium 
to 9-seriate, scattered; sperms 2, division horizontal; basal cell elongate; 
terminal cell apically obtuse; vegetative cell 12-16 35-144y; oogonium 
34-50 X 34-55; oospore 31-41 X30-41y4; antheridium 11-15X5-7uy. 
United States: Iowa, New Jersey, Illinois; Patagonia; 
Austria, Finland, Sweden; South Africa. 
The typical plants of this species have a nearly superior 
pore, and the oospore usually does not fill the irregularly 
shaped oogonium. Transeau has observed both dioecious and 
monoecious forms from Illinois. -(See also Hirn Joc. cit.). 
11. Oc. urbicum Wittrock. 
(Pl. XII, figs. 118 and 119.) 
1874, 13; Oe. tumidulum Pringsh. 1855, p. 158, Pl. 1, figs. 26 and 27; Hirn 
1900, p. or. Pl. V, fig. 26. 
Monoecious; oogonium 1, ellipsoid-globose, pore a little above 
median or nearly superior; oospore globose, not filling oogonium, spore 
wall smooth; antheridium few celled; sperms 2, division horizontal; 
vegetative cell 15-19X40-110u; oogonium 46-55 X58-63u; oospore 
33-46 X 33-46u; antheridium 14-16 5-7u. 
Germany. 
In general appearance this species is similar to Oe. varians 
above and Oe. tyrolicum (No. 14). It is distinguished from the 
former by its size and tendency toward ellipsoid oogonia; 
from both by the variable position of the pore. 
12. Oe. obsoletum Wittrock. 
(PI. XII, fig. 121.) 
1874, p. 9; Oe. vernale Wittr. 1872, p. 1; Hirn 1900, p. 83, Pl. II, fig. 16. 
Monoecious; oogonium 1, subglobose or subdepressed-globose, pore 
a little above supramedian; oospore subdepressed-globose, not filling 
oogonium, spore wall smooth; antheridium 1-3, subepigynous; sperm 1; 
vegetative cell 9-15X30-75u; oogonium 34-39X34-438u; oospore 
30-34 & 28-32u; antheridium 8—9X 12—16uy. 
United States: Pennsylvania; England, Sweden. 
Similar to Oe. plusiosporum below and distinguished from 
it by the usually depressed-globose appearance of the oospore. 
The oospore of Oe. plusiosporum is more regularly globose and 
its oogonium is more nearly ellipsoid. 
