OEDOGONIUM 15: 
Ol 
- 
The species is characterized by its scrobiculate oospore, wide 
operculum, enlarged suffultory cell, and usually many-seriate 
oogonia. Var. eminens is much larger and f. borgei is con- 
siderably larger than the type; f. victoriense is near f. borgei, 
differing in the size of the oospore. 
189. Oe. obtruncatum Wittrock. 
(Pl. LIX, fig. 577.) 
1874, p. 41; Hirn 1900, p. 284, Pl. XLIX, fig. 318. 
- Dioecious, nannandrous, gynandrosporous; oogonium 1-6, ellipsoid, 
or globose-ellipsoid, operculate, division supreme, operculum small and 
deciduous; oospore of same form as oogonium, nearly filling it, spore 
wall smooth; vegetative cell evidently capitellate; basal cell elongate; 
terminal cell (often the oogonium) apically obtuse; dwarf male oblong- 
pyriform, curved, unicellular, on oogonium; vegetative cell 18-22 
56-110u; oogonium 45-55 56-68u; oospore 48-53 52-664; andro- 
sporangium 2024u; dwarf male stipe 17—-2036-40u; antheridium 
6-8 X 4-6. 
United States: Ohio, Illinois; England; Brazil; India; Aus- 
tralia. 
189a. Var. completum Hirn. 
(Pl. LIX, figs. 579-582. ) 
1900, p. 285, Pl. L, fig. 319. 
Oogonium larger; androsporangium 1-5, hypogynous or subepigynous 
or epigynous; terminal cell sometimes setiform; vegetative cell 18-22 
66-150n; oogonium 55-58 X63-75u; oospore 538-5661-73yu; andro- 
sporangium. 20-22 x 19-22. 
Bengal. 
189b. Var. ellipsoideum Wittrock. 
(Pl. LIX, fig. 578.) 
1878, p. 141; Hirn 1900, p. 286, Pl. L, fig. 320. 
Oogonium longer, ellipsoid, 1-2, terminal; vegetative cell 17-23 
54-110u; oogonium 42-54 « 66—-75u. 
Venezuela. a 
Oe. obtruncatum is characterized by the usually capitellate 
vegetative cells, supreme position of the operculum, unicellular 
nannandrium, and gynandrosporous habit. The two varieties 
completum and ellipsoideum are separable largely on the basis 
of differently sized oogonia. The species is much larger than the 
gynandrosporous Oe. wabashense (No. 192). It is perhaps 
nearest in general appearance to Oe. praticolum (No. 190) and 
Oe. supremum (No. 191), both of which are idioandrosporous 
and have larger oogonia. 
