Q4 cH. (On ©.GON EAC BAw 
58. Oe. arcyosporum Nordstedt and Hirn. 
(Pl. XXVIII, fig. 247.) 
In Hirn 1900, p. 104, Pl. VII, fig. 44. 
Monoecious; oogonium 1-5, obovoid to ellipsoid-globose, pore 
superior; oospore ellipsoid-globose to subglobose, not usually filling 
oogonium, spore wall of three layers: outer smooth, median areolate, 
inner smooth; antheridium 1-4, subepigynous to subhypogynous; 
vegetative cell 138-2050-200u; oogonium 41—-55x43-68u; oospore 
38-50 X 40-55u; antheridium 11-15 X8-12uy. 
Brazil. 
The only monoecious form with an areolate oospore wall. 
59. Oe. areolatum Lagerheim. 
(Pl. XXVIII, figs. 248-250.) 
1890, p. 80 and 89; Hirn 1900, p. 105, Pl. VII, fig. 45; Tiffany 1926, p. 91. 
Dioecious, macrandrous; oogonium 1-4, obovoid or obovoid-globose, 
with superior pore; oospore subellipsoid or ellipsoid-globose, filling or not 
filling oogonium, middle layer of spore wall areolate; antheridium 3-12, 
sperms 2; basal cell elongate; terminal cell apically obtuse; female 
vegetative cell 16-21X65-165u, male 15-19X60-140u; oogonium 
48-60 X 60-75; oospore 45-57 X 48-60yu; antheridium 14-17 X8-10u. 
United States: Iowa, Ohio; Ecuador, Brazil. ae 
This species is to be compared with Oe. hoehnez (No. 202). 
It is one of the few dioecious macrandrous forms with areolate 
oospores. 
60. Oc. dictyosporum Wittrock. 
(Pl. XXVIII, fig. 246.) 
1874, p. 13; Hirn 1900, p. 103, Pl. VII, fig. 43; Tiffany 1926, p. 99. 
Monoecious; oogonium 1-2, obovoid-globose, with superior pore;> 
oospore globose to ellipsoid-globose, usually not filling oogonium, outer 
layer of spore wall reticulate, inner smooth; antheridium 1-8, sub- 
epigynous; sperms 2; vegetative cell 11-16 25—-95yu; oogonium 33-40 
38-46u; oospore 28-38 x 30—-40u; antheridium 8-13 X5-10n. 
United States: Iowa; Brazil; Africa. 
60a. Form westii Tiffany. 
1929, p. 74; Oe. dictyosporum Wittr. forma West 1907, p. 98. 
Oogonium and oospore ovoid-ellipsoid; a little larger; vegetative 
cell 14-16 X50-80u; oogonium 42% 52u; oospore 40 50u; antheridium 
13 X8—9un. 
Africa. 
The only monoecious representatives of the genus with 
reticulate oospores are Oe. dictyosporum and its f. westiz. The 
latter is a little larger than the type and is better recognized 
as a form until we have more data on its distinctive character- 
istics. 
