162 TRE ORDIOGCONTUNG EAE 
. 
203. Oe. fusus Hallas. 
(Pl. XXXIV, fig. 311.) 
1905, p. 407, fig. 15; Hirn 1906; p. 14, Pl. IV, fig. 26. 
(?) Dioecious; oogonium 1, ellipsoid, operculate, division median; 
oospore globose, not filling oogonium, spore wall smooth; vegetative 
cell 2-3 < 10-23u; oogonium 14-15 31-35y; oospore 12 12y. 
Denmark. 
Characterized by its small size and ellipsoid oogonium with 
globose oospore. Cf. Oe. inconspicuum (No. 198) and Oe. 
pusillum (No. 200). 
204. Oe. rhodosporum (Welwitsch) Wittrock. 
(Pl. XL, figs. 388 and 389.) 
1874, p. 34; De Toni 1889, p. 72; Hirn 1900, p. 305, Pl. XXXI, fig. 193. 
Dioecious (? macrandrous or nannandrous); oogonium 1-3, obovoid 
to globose obovoid, operculate, division superior; oospore same form as 
oogonium, nearly or quite filling oogonium, spore wall smooth; antherid- 
ium (? androsporangium) =o; vegetative cell 16-23 X 20— -66u; oogonium 
35-44 X 45-54; oospore 33-41 X 38-484; antheridium (? androsporang- 
ium) 16-19X9-17p. 
France, Portugal. 
To be compared with Oe. pluviale (No. 183) and with the 
two following species. 
205. Oe. vesicatum (Lyngbye) Wittrock. 
(Pl. XL, figs. 386 and 387.) 
Conferva vesicata Lyng. 1819, p. 140, Pl. 47, fig. D1; Oe. vesicatum Wittr. 1874, 
p. 39; Hirn 1900, p. 306, Pl. XXXI, fig. 194. 
Dioecious, oogonium 1, obovoid or globose-obovoid, operculate, © 
division superior; oospore same form as oogonium which it nearly fills, 
spore wall smooth; antheridium (? androsporangium) 1-4; vegetative 
cell, female 17-23 X 22-74: male (? androsporangial) 16— -21X28-63y; 
oogonium 40-45 x 49-60u; oospore 35-42 X 40-48; antheridium C and- 
rosporangium) 16-18 X 11-16p. 
Denmark. 
Cf. Oe. rhodosporum above and Oe. montagne below. 
206. Oe montagnei Fiorini-Mazzanti. 
(Pl. XL, figs. 390 and 391.) 
1860, p. 259, Pl. 1, figs. 1, 2 and 5; Wittrock 1874, p. 41; Hirn 1900, p. 307, Pl. 
XXXI, fig. 195. 
Oogonium 1-2, obovoid or globose-obovoid, operculate, division 
superior; oospore of same form as oogonium, filling it or nearly so, 
spore wall smooth; vegetative cell 18-26 x 20- 1104; oogonium 40-52 
48—65u; oospore 38 47 X43— —52u. 
Italy. 
Cf. Oe. rhodosporum (No. 204) and Oe. vesicatum (No. 205). 
