OEDOGONIUM 101 
Dioecious, macrandrous; oogonium 1, globose, operculate, division 
. inferior; oospore globose, quite filling the oogonium, spore wall smooth; 
antheridium 1-8; sperm-1; vegetative cell capitellate; basal cell sub- 
hemispherical, not elongate; filament not infrequently incrusted with 
lime; female vegetative cell 12-14X25-100u, male 9—-11X20-80y; 
oogonium (28-) 32-35X30-34u; oospores (27—-) 30-382X27-30u; 
antheridium 10-12 9-12u; basal cell 13-20 7-14u. 
United States: Iowa; Australia; Austria, France, Germany, 
Sweden, Switzerland; Africa. 
Easily distinguished among the macrandrous species by the 
inferior position of the operculum. It is in some respects 
similar to Oe. infimum below. The f. subclusum, according to 
the Iowa material (Tiffany 1926), is merely an ecological 
variant and is not tenable. The variations of the species 
proper include the form. 
78. Oc. infimum Tiffany. 
(Pl. XXXIII, figs. 289-292.) 
1924, p. 183, Pl. II, figs. 6-9; 1926, p. 95, Pl. VI, figs. 59-62. 
Dioecious, macrandrous; oogonium 1, globose or subglobose (or the 
basal part extended, appearing subpyriform-globose), operculate, 
division at the lowest extremity of the oogonium; oospores globose or 
subglobose, membrane smooth; male plants a little larger than the 
female; antheridium 1-10; sperms 2; vegetative cells distinctly capitel- 
late; basal cell of filament subhemispherical, not elongated; filaments 
not infrequently incrusted with lime; female vegetative cells 12-18 
60-140u, male 16—-2060-140u; oogonium 40-48X41-50u; oospore 
40-44 X 38-42u; antheridium 14-208-12u; basal cell 30-42 16-24. 
United States: Iowa. 
Oe. infimum is the only known member of the genus with the 
operculum located at the lowest extremity of the oogonium. 
It is further characterized by its evidently capitellate vegetative 
cells. 
79. Oe. howardii West. 
(Pl. XXXIII, fig. 293.) 
1904a, p. 281, Pl. 464, figs. 1-5; Hirn 1906, p. 16, Pl. III, fig. 9. 
Dioecious, macrandrous; oogonium 1-2, globose (or subglobose), 
operculate, division median, distinct; oospore globose (or subdepressed- 
globose) filling oogonium; antheridium to 16-seriate, sperm (?) 1; vege- 
tative cell broadly capitellate; basal cell subhemispherical, scarcely 
elongate; vegetative cell, female 9-1220-44u; male 7-9X16-35y; 
oogonium 29-33 X29-33u; oospore 25-29 X25-29u; antheridium 7-9 X 
8—14u; basal cell 14-16 10-11. 
West Indies: Barbados. 
