OEDOGONIUM 119 
spore wall smooth, sometimes thick; androsporangium to 7-seriate; 
vegetative cell undulate (4 undulate constrictions); basal cell elongate, 
not undulate; terminal cell (sometimes oogonium) apically obtuse; 
dwarf male elongate-obconic, usually on suffultory cell, rarely on other 
vegetative cell near oogonium, antheridium interior; vegetative cell 
15-22 45-1104; oogonium 48-56X50-75u; oospore 42-50 42-52 
(-60)u; androsporangium 15-21X7-14y; dwarf male 8-10X48-65 
(—70) u. 
United States: Michigan, Florida, Indiana; Uruguay; Aus- 
tralia; Manchuria, China; Austria, England, Finland, -France, 
Germany, Norway, Poland, Sweden, Russia, Latvia; Columbia; 
Africa (Victoria). 
119a. Var. americanum Transeau. 
(Pl. XLII, fig. 408.) 
1917, p. 232. 
Vegetative cell as in type; oogonium much larger; vegetative cell 
15-22 X 45-110u; oogonium 58-68 x 60-80; oospore 48-60 X 48-56y. 
United States: Michigan. 
119b. Form senegalense (Nordstedt) Hirn. 
(Pl: XLII, fig. 409.) 
1900, p. 261, Pl. XLV, figs. 276 and 277; Oe. undulatum (Breb.) A. Br. var. 
senegalense Nordst. 1880, p. 138; P. B. A. No ees 
Oogonium and oospore smaller than the type; dwarf male shorter; 
oogonium to 5-seriate; vegetative cell with three median swellings 
repand, the terminal swelling entire, 15-22 45-110u; oogonium 42-52 x 
44-63; oospore 37-44 K 36-44; androsporangium 15-19X9-18u; dwarf 
male 6-8 X 37-44u. 
United States: Massachusetts; Africa: Senegal. 
The undulate vegetative cells are characteristic. It bears 
some relation in the vegetative state to Oe. nodulosum (No. 96). 
The var. americanum has considerably larger oogonia than the 
.type and f. senegalense has slightly smaller fruiting cells. A 
number of variations of this species are on record in algological 
literature, but the two above seem the only really tenable ones 
outside the species proper. 
120. Oe. nebraskense Ohashi. 
(Pl. XLII, figs. 410-413. ) 
Oe. nebraskensis Ohashi 1926, p. 213, figs. 1-20. 
Dioecious, nannandrous, gynandrosporous; oogonium 1-4, flask- 
shaped or obovoid, pore supramedian; oospore subspherical or ovoid, not 
quite filling oogonium, outer layer of spore wall smooth, middle layer 
punctate, inner layer smooth; androsporangium 1-4, basal cell elongate; 
terminal cell attenuate-obtuse; dwarf male curved, on suffultory cell, 
