68 THE OEEDOGONIMVCEAE 
inner smooth; antheridium 1-4, subepigynous, subhypogynous, 
hypogynous, or scattered; sperm 1; vegetative cell 8-19X32-70n; 
oogonium 30-40 27—40u; oospore 27-35 X 22-33y; antheridium 7-10 
9=1dp: 
United States: Massachusetts, Mississippi; Austria, England, 
Finland, France, Hungary, Sweden. 
This species resembles Oe. magnusit below from which it 
is distinguished by its monoecious habit, its larger oogonia, 
and its oospores not usually filling the oogonia. 
8. Oe. magnusii Wittrock. 
(Pl. XII, fig. 115.) 
1874, p. 38; Hirn 1900, p. 81, Pl. II, fig. 14; Wittr. and Nordst. Alg. Ex. No. 109. 
Dioecious, macrandrous (perhaps monoecious also); oogonium 
1-3, depressed-globose, pore median, rimiform; oospore depressed- 
globose, quite filling oogonium, spore wall of three layers: outer layer 
smooth, middle layer scrobiculate, inner layer smooth; antheridium 
to 8-seriate, sperm 1; vegetative cell 7-10X 12—40u; oogonium 24-27 X 
21-264; oospore 22-25 X 18-23y; antheridium 8-10X5-1 1x. 
United States: Illinois, Michigan, Massachusetts; British 
Columbia; Finland, Germany, Sweden. 
Easily separable from Oe. cymatosporum (No.7). According 
to Wittrock it is sometimes monoecious. 
9 Oe. suecicum Wittrock. 
(Pl. XII, fig. 116.) 
1872, p. 5; 1874, p. 30; West 1891, p. 109, Pl. 18, fig. 2; (?) Oe. trichosporum 
Itzig. in Rabenh. 1868, p. 426; Hirn 1900, p. 82, Pl. II, fig. 15; Collins 1909, p. 230; 
Heering 1914, p. 198, fig. 281; Tiffany 1926, p. 89, Pl. V, figs. 57 and 58. 
Dioecious, macrandrous; oogonium 1, subglobose, pore median; 
oospore globose, nearly filling oogonium, outer spore wall echinate, inner 
smooth; antheridium 2-6, sperm 1; basal cell elongate; terminal cell 
apically obtuse; vegetative cell 9-14 X 30-90; oogonium 32-38 XK 34-41; 
oospore 30-37 X30-37y; antheridium 10-12 X 13-17. 
United States: Iowa, Illinois, Massachusetts; Australia; 
Austria, Denmark, Finland, France, Germany, Latvia, Iceland, 
Norway, Sweden; British Columbia; South Africa. 
Qa. Form australe G. S. West. 
i (Pl. XII, fig. 117.) 
1909, p. 45, fig. 6 E. 
Vegetative cell somewhat larger; spines larger and moré sparse; 
vegetative cell 14-16X56-80y4; oogonium 40-41 40-414; oospore 
(without spines) 31-33 X31-33u. 
Africa: Yan Yean Reservoir, Victoria. 
The species and the variety constitute the only dioecious 
macrandrous members of the genus having echinate oospores. 
