164 Es) Ou D O'G ONDA CE AE 
209a. Var. seriosporum (Lagerheim) Hirn. 
(Pl. XXI, figs. 191 and 192.) 
1900, p. 294, Pl. XXII, fig. 114; Oe. seriosporum Lagerh. 1888, p. 590. 
More variable, oogonium sometimes 2-5, lower series of oogonium 
_ subcylindric or cylindric-globose; vegetative cell 24-42 (-54) X38-120y; 
oogonium, single or wpper series, 48-6060—-99y, lower series 42-54 
(35—-) 48-52u; oospore 40-56 & 40-75y. 
Germany. 
Characterized by the variation in the size of the oogonia 
and the vegetative cells on the same plant, the species is some- 
what near Oe. mexicanum (No. 44). The variety is even more 
variable than the species, and its oogonia are more seriate. 
210. Oe. virceburgense Hirn. 
(Pl. XXXVI, fig. 336.) 
1896, p. 8; 1900, p. 301, Pl. XXIV, fig. 128; 1906, p. 54. 
Oogonium 1-8, subpyriform- to subdepressed-globose, operculate, 
division a little above median; oospore subdepressed- or depressed- 
globose, quite filling oogonium, spore wall smooth; vegetative cell often 
broadly capitellate; basal cell half round; vegetative cell 4-6 X 138-45; 
oogonium 15-20 15-23y; oospore 14-19 X 14-17u. 
Austria, Germany, Hungary. 
To be compared with the slightly larger Oe. spurium (below) 
and with Oe. petri (No. 90). 
211. Oe. spurium Hirn. 
(Pl. XXXVI, fig. 333.) 
1900, p. 301, Pl. XXIV, fig. 131. 
Oogonium single, subdepressed- or depressed-globose, operculate, 
division supramedian; oospore of the same form as oogonium, nearly 
or completely filling it, spore wall smooth; vegetative cell capitellate; 
basal cell elongate; terminal cell apically obtuse or truncate-obtuse; 
vegetative cell 9-13 X 20-55y; oogonium 26-29 X 23-28; oospore 24-28 X 
21-24. 
United States: Ohio; Brazil. 
Cf. Oe. virceburgense above. It also has considerable 
resemblance to the longer celled filaments of Oe. sphaerandrium 
(No. 105). 
212. Oe. velatum Hallas. 
(Pl. XLI, figs. 398 and 399.) 
1905, p. 405, fig. 11; Hirn 1906, p. 23, Pl. IV, fig. 27. 
Oogonium single, ellipsoid-globose, operculate, division superior; 
oospore globose, not filling oogonium, middle layer of spore wall echinate; 
vegetative cell 3-20 25--400u; oogonium 4368; oospore 35X35y. 
Denmark. 
