116 ia) OE DOIG ON EAC EAE 
113. Oe. kirchneri Wittrock. 
(Pl. XXXVIII, fig. 371.) 
F ae p. 104; Oe. alternans Kirch. 1878, p. 53; Hirn 1900, p. 183, Pl. XXIX, 
Ze i 
Monoecious; oogonium 1, ellipsoid or obovoid-ellipsoid, operculate, 
division superior; oospore of same form as oogonium, nearly filling 
oogonium, spore wall smooth; antheridium 1-2, hypogynous and 
alternating with oogonium; sperms 2, division horizontal; terminal cell 
obtuse; vegetative cell 8-15x16-60u; oogonitum 20-2434 -48y; 
oospore 19-23 X 32-41; antheridium 9-13 X4—7u. 
Germany. 
Chiefly characterized among those with ellipsoid, operculate 
oogonia by the alternation of oogonium and antheridium. 
114. Oe. gracillimum Wittrock and Lundell. 
(Pl. XXXVIII, fig. 373.) 
In Wittr. 1874, p. 15; Wolle 1887, p. 74, Pl. 75, fig. 2; Hirn 1900, p. 184, Pl. 
XXIX, fig. 180; Collins 1909, p. 247; Heering 1914, p. 218, fig. 318; Tiffany 1926, 
p.100; Piva eg. 9. 
Monoecious; oogonium 1, oblong, operculate, division superior; 
oospore oblong-ellipsoid, not filling oogontum, spore wall smooth; 
antheridium 1; sperms 2, division horizontal; basal cell elongate; 
vegetative cell 4-7 x 16-42y; oogonium 14-19 X 34—40y; oospore 13-17 X 
' 24-32u; antheridium 3-5 X4-7n. 
United States: Iowa, Pennsylvania, Michigan, Illinois, Ohio, 
Mississippi, Kentucky; Sweden; Angola. 
114a. Form majus West and West. 
1897, p. 4; Hirn 1900, p. 184. 
Vegetative cell 6-7X20-40u; oogonium 20-2332-35u; oospore 
17 X24u. 
Africa. 
Oe. gracillimum almost invariably has some oogonia with 
imperfectly developed oospores. 
115. Oe. oblongellum Kirchner. 
(Pl. XXXVIII, fig. 372.) 
In Hirn 1900, p. 182, Pl. X XIX, fig. 177. 
Monoecious; oogonium 1, ellipsoid-obovoid, operculate, division 
superior; oospore ellipsoid, nearly filling oogonium, spore wall smooth; 
antheridium 1-2, hypogynous or scattered; sperms 2, division hori- 
zontal; terminal cell obtuse; vegetative cell 7-9X 14—-35yu; oogonium 
20-24 & 25-33u; oospore 18-22 X 24-30yu; antheridium 6-8 X4—12u. 
United States: Illinois, Mississippi; Germany; Burma. 
Oe. oblongellum is near Oe. oblongum, below, but the latter 
almost invariably has oogonia not filled lengthwise by oospores; 
the former has oogonia nearly completely filled.: 
