OEDOGONIUM 161 
200. Oe. pusillum Kirchner. 
(Pl. XXXIV, fig. 316.) 
1878, p59; (?) Oe. excisum Wittr. and Lund. in Nordst. 1880, p. 13; Oe. africanum 
Lagerh. 1893, p. 155; Oe. Klebahnit Lemm. 1893, p. 509, and 1895, p. 28, figs. 4 and 5; 
ibid. in De Wildemann 1896, p. 66, Pl. 5, figs. 2-7; Oe. africanum Lagerh. in Lemm. 
1896, p. 502, Pl. 5, figs. 3-20; Hirn 1900, p. 299, Pl. XXIV, fig. 125; Collins 1912, p. 
88; Heering 1914, p. 224, fig. 345; Tiffany 1926, p. 95, Pl. VII, fig. 80. 
Oogonium 1 (rarely 2), subbiconic-ellipsoid or subbiconic-globose, 
seen from above circular, margin even, operculate, division wide; 
oospore ellipsoid or globose, generally constricted at the middle, not 
quite filling oogonium, spore wall smooth; basal ce!l subhemispherical; 
terminal cell obtuse or obtusely conical; vegetative cell 3-6 10—-60y; 
oogonium 14-16 X 15-254; oospore 11-13 X 13—-15y; basal cell 7-8 x 7-8yu. 
United States: Iowa, Illinois; Austria, France, Germany; 
Africa; Brazil; Sumatra. 
This species is usually very readily recognized by its 
medianly constricted oospore, and whether eventually found to 
be monoecious or dioecious, it is a distinct species. 
201. Oc. selandiz Hallas. 
(Pl. XXXVIII, fig. 359.) 
1905, p. 496, fig. 14; Hirn 1906, p. 20, Pi. ITI, fig. 11. 
(?) Monoecious; oogonium 1-2, oblong (or angular-oblong), opercu- 
late, division superior; oospore oblong-ellipsoid or obovoid, completely 
filling oogonium or not; vegetative cell 3-5 X 13-40u; oogonium 9-14 X | 
27-30u; oospore 7-12 X 16-25py. 
Denmark. 
To be compared with Oe. gracillimum (No. 114) and with 
Oe. rugulosum (No. 179). 
202. Oe. sancti thomee Wittrock and Cleve. 
(Pl. XXXVIII, fig. 360.) 
In Witt. 1874, p. 40; 1878, p. 141; Hirn 1900, p. 304, Pl. XXIX, fig. 173; Collins 
1909, p. 265. 
Oogonium 1-3, pyriform, operculate, division superior; oospore 
pyriform-obovoid, not quite filling oogonium, spore wall smooth; 
basal cell subhemispherical; terminal cell very slender, subhyaline; 
vegetative cell 7-15 X 16-88y; oogonium 28-33 XK 36—-50u; oospore 25-30 X 
28-35; basal cell 14-23 X8-12uy. 
United States: Mississippi, Ohio; West Indies (St. Thomas). 
Material from Mississippi and Ohio have been referred to 
this species, although antheridia were not observed. It is 
perhaps dioecious, macrandrous. 
