106 THE -O EBD OGOMIACEAE 
depressed-globose, filling oogonium, spore wall smooth; antheridium 
1-2, hypogynous or epigynous or subepigynous; sperm 1; basal cell 
elongate; terminal cell apically obtuse; vegetative cell 6-7 32—48u; 
oogonium 21-24 22-29y; oospore 20-23 X 16-19u; antheridium 5-7 X 
9-11. 
Germany, Spain, Sweden; Ceylon. 
91. Oe. trioicum Woronichin. 
1923, p. 99. 
Dioecious macrandrous, or monoecious; oogonium 1-3, sometimes 
terminal, ellipsoid, operculate, division superior; oospore ellipsoid or 
subovoid, spore wall smooth, faintly violet; antheridium 1-6, hypogy- 
nous in monoecious filament, scattered or terminal in male filament; 
terminal cell obtusely rounded; basal cell attenuate; male plants 
130-330 long; vegetative cell 4—5 x 12-22u; oogonium 25-27 x 138-16y; 
oospore 20-21 X 14y; antheridium 4X 3uy. 
Near Baku, in Azerbaijan (west coast of the Caspian). 
This plant according to Woronichin is both dioecious, 
macrandrous and monoecious, in this respect similar to Oe. 
varians (No. 10). It should be compared with the macrandrous 
pringsheimit (No. 95) and the monoecious gracillimum (No. 114). 
Unfortunately no figure is available. 
92. Oc. welwitschii West and West. 
(PI. XXXVI, figs. 351 and 352.) 
1897, p. 5; Hirn 1900, p. 174, Pl. XXVIII, fig. 162; Tiffany 1926, p. 97, Pl. IV, 
figs. 41 and 42. 
Dioecious, macrandrous; oogonium 1-38, subovoid-globose, opercu- 
late, division superior; oospore globose, filling or not filling oogonium, . 
spore wall smooth; antheridium 2; female vegetative cell 20-28 X 25-84, 
male 17-20 X 35-80y; oogonium 43-50 X 43-52y; oospore 35-43 X 35—-42y; 
antheridium 16-18 X 7—9u. 
United States: Iowa, Illinois, Alabama; Africa. 
This species is near Oe. iowense below, but differs in having 
at once both larger vegetative cells and smaller oogonia. It 
may be near the imperfectly known dioicum (No. 94) and is 
larger than Oe. pringsheimii (No. 95). 
93. Oc. iowense Tiffany. 
(Pl. XXXVII, figs. 353-355. ) 
1924, p. 181, Pl. III, figs. 1-3; 1926, p. 97, Pl. VI, figs. 69-71. 
Dioecious, macrandrous; oogonium 1-2, globose, or ellipsoid-globose, 
operculate, division superior; oospore of the same form as the oogonium, 
which it completely fills or not, spore wall smooth; antheridium 1-25, 
sperms 2, division horizontal; basal cell of filament commonly elongated; 
vegetative cell 10-16X44-100u; oogonium 52-60X60-80u; oospore 
45-56 X 50-644; antheridium 10-12 10-20y; basal cell 16-24 60-80y. 
