110 Lie © PDOGORerA CELE 
99a. Var. gracilis Transeau and Tiffany. 
(Pl. XXXVIII, figs. 365 and 366.) 
1919, p. 241; Tiffany 1926, p. 98, Pl. III, figs. 31-34. 
Oogonium and oospore ellipsoid to ellipsoid-ovoid; vegetative cell, 
female 6-9X18-48u, male 5-8X16-45yu; oogonium 16-20 20-30u; 
oospore 15-18 X 18-28u; antheridium 5-7 X5-10y. 
United States: Iowa, Illinois, Mississippi. 
The combination of small size, elongate basal cell, and 
piliferous terminal cell is sufficient to characterize the species. 
The presence of subhemispherical basal cells in Oe. nanum 
(No. 98) easily separates it from Oe. pisanum. The variety 
gracilis is smaller. Often epiphytic on other species of algae. 
100. Oc. pyriforme Wittrock. 
(Pl. XXXVI, fig. 348.) 
1874, p. 39; Hirn 1900, p. 303, Pl. XXV, fig. 137. 
Monoecious; oogonium 1, pyriform, operculate, division superior; 
oospore pyriform, filling or not filling oogonium, spore wall smooth; 
antheridium 1-3, subepigynous, epigynous, hypogynous, or scattered; 
sperms 2, division horizontal; vegetative cell 13-16 X48—90u; oogonium 
40-46 X (44-)48-60u; oospore 36-4236-44y; antheridium 10-12 
8-12u. 
Tasmania; British Columbia. 
The pyriform oogonium is characteristic. The dimensions 
of Oe. pyriforme separate it from Oe. simplex (No. 102) and Oe. 
pyrulum (No. 103). Originally found in Tasmania, the above 
complete description 1s furnished from material collected in 
British Columbia by Mr. G. H. Wailes. 
101. Oe. gunnii Wittrock. 
(Pl. XXXIV, fig. 318.) 
1874, p. 37; Hirn 1900, p. 298, Pl. XXIII, fig. 119. 
Monoecious; oogonium 1-4, subdepressed- or depressed-globose, 
operculate, division median, narrow but distinct; oospore same form as 
oogonium and filling it, spore wall smooth, outer layer thick and hyaline, 
inner brown; antheridium subepigynous; vegetative cell 6-9 X30-85y; 
oogonium 23-29 X 19-294; oospore 22-27 X 17—23u; antheridium 6 X 12u. 
United States: Alabama; Australia. 
Material collected in Alabama by Professor E. N. Transeau 
shows Oe. gunnii to be definitely monoecious. Its distinctly 
narrow median division of the oogonium separates it from the 
imperfectly known Oe. poecilosporum (No. 224). 
