118 THE OEDOGONIACEAE 
117a. Form heteromorphum Hirn. 
(PI. XXXIX, fig. 381.) 
1900, p. 178, Pl. XXVIII, fig. 168. 
Processes on oogonium intermediate between conically obtuse 
projections and mammiform protuberances; vegetative cell 6-9X 
30-110u; oogonium 33-40 35-40y; oospore 20-25 x 20-25n. 
Germany, Sweden. 
= 117b. Var. minus West. 
(Pl. XXXIX, fig. 382.) 
1893, p. 97; 1897, p. 4; Hirn 1900, p. 178, Pl. XXVIII, fig. 169. 
Smaller; processes of oogonium acutely rounded; vegetative cell 
5-7 X 25-70u; oogonium 28-30 X 28-30u; oospore 16-20 X 16—20y. 
England. 
Oe. itzigsohnii is near Oe. mammiferum below, but differs in 
having conically obtuse projections, instead of mammiform 
projections, on the oogonia. Var. minus is slightly smaller 
than the type and f. heteromorphum has oogonial projections 
somewhat intermediate between the species proper and Oe. 
mammiferum. 
118. Oe. mammiferum Wittrock; Nordstedt. 
(Pl. XXXIX, figs. 383-385. ) 
- Wittr. 1874, p. 16; Nordst. 1877, p. 25, Pl. 3, figs. 4-6; Oe. huillense Wesi 1897, 
p. 5, Pl. 365, figs. 7 and 8; Hirn 1900, p. 175, Pl. XXVIII, figs. 165 and 166. 
Monoecious; oogonium 1 (rarely 2-3), ellipsoid, with mammiform 
projections appearing as 7-9 radiations seen vertically, operculate, 
division inframedian, very narrow; oospore globose or subdepressed- . 
globose (rarely depressed-globose), not filling oogonium, spore wall 
smooth; antheridium 1, subepigynous; basal cell elongate; vegetative 
cell 5-8 X20-56u; oogonium 20-28 X20-30u; oospore 12-17 (-20) Xx 
12—16u; antheridium 6X 7u. 
United States: Massachusetts; Norway, Sweden; India; 
Africa. : 
Cf. Oe. ttzigsohni above. 
119. Oe. undulatum (Brebisson) Al. Braun; Wittrock. 
(Pl. XLII, fig. 407. ) 
Conferva undulata Breb.; Oe. undulatum Al. Braun in De Bary 1854, p. 94; 
Wittr. 1870, p. 130; Cymatonema confervaceum Kuetz. 1849, p. 375 and 1853, p. 15, 
Pl. 47, fig. 1; Borge 1899, p. 4, Pl. 1, fig. 2; Oe. undulatum A. Br. var. interrupte- 
incisum Schroeder 1897, p. 10, Pl. 2, fig. 1; Oe. sp. Moebius 1894, p. 320, Pl. 1, fig. 
21; Oe. undulatum A. Br. var. Moebiusii Schmidle 1896, p. 297, Pl. 9, fig. 1; Oe. 
undulatum (Breb.) Al. Br. var. Moebiusii Schmidle in Borge 1896, p. 5; Hirn 1900, - 
p. 257, PI. XLV, figs. 272-275. : 
Dioecious, nannandrous, gynandrosporous or idioandrosporous; 
oogonium 1-2, subglobose or ellipsoid-globose, operculate, division 
inferior, wide; oospore globose or subglobose, quite filling oogonium, 
