TA Ee OF DOiGONDAC EAE 
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29a. Var. fennicum Hirn. 
(Pl. XVI, fig. 158.) 
1895, p. 14; 1900, p. 116, Pl. XII, fig. 61. 
Oogonium and oospore larger, ellipsoid; vegetative cell 13-20 
55-175u; suffultory cell 25-33x40-66u; oogonium 63-68 X75-85y; 
oospore 61-64 X 70-78y; antheridium 15-20 8-13yu 
Finland. 
This smooth-spored species is one of a few in the genus 
combining the monoecious habit with the tendency toward 
ellipsoid oogonia. It is distinguished from Oe. oviforme (No. 30) 
by its slightly smaller size, its varying diameter of vegetative 
cell, and by the rather characteristic alternation of antheridium, 
oogonium, and vegetative cell in the filament. Oe. sodiroanum 
(No. 28) is smaller and has shorter vegetative cells. Oe. 
upsaliense bears some resemblance to Oe. richterianum (No. 26) 
but in the latter the sperms result from a horizontal division 
of the antheridium, not a vertical division. The variety 
fennicum has much larger oogonia and antheridia. The smaller 
suffultory cell is usually characteristic of both the species and 
the variety. 
30. Oe. oviforme (Lewin) Hirn. 
(Pl. XVI, fig. 152.) 
1900, p. 116, Pl. XII, fig. 62; Oe. urbicum Wittr. var. oviforme Lewin 1888, 
p. 17, Pl. 2, fig. 48; Heering 1914, p. 210, fig. 308; Tiffany 1926, p. 100, Pl. VIII, 
figs. 78 and 79. 
Monoecious; oogonium 1, obovoid to ellipsoid-obovoid, pore superior; 
oospore obovoid to ovoid (rarely almost globose), filling or not filling the _ 
oogonium, spore wall smooth, thick; antheridium 1-4, epigynous, 
hypogynous, or scattered; sperms 2, division vertical; basal cell 
elongated; vegetative cell 15-23X40-135u4; oogonium 48-55 xX (56-) 
65-80u; oospore 46-53 X 50-63u; antheridium 16-19 X 7-12uy. 
United States: Iowa; Spain. 
The material distributed from Spain shows a more uniformly 
obovoid oogonium than is common in the Iowa samples: the 
latter approach the ellipsoid-obovoid variation. Cf. Oe. upsal- 
zense (No. 29). 
31. Oc. geniculatum Hirn. 
(Pl. XVI, fig. 155.) 
1900, p. 106, Pl. VIII, fig. 48; P. B. A. No. 411. 
Monoecious; oogonium 1, obovoid or obovoid-globose, pore superior; 
oospore globose or subdepressed-globose, not filling oogonium, spore 
wall smooth and thick; antheridium 1—5, subepigynous or subhypogy- 
nous or scattered, sometimes alternating with vegetative cells; sperms 
(?) 2, division (?) horizontal; vegetative cell 37-48 X 60-135; oogonium 
56-63 X 56-684; oospore 48-59 X48—59u; antheridium 37-44 X5—-Qup. 
