THE GRBEN ALGAE OF NORTH AMERICA 67 



XXIX, fig. 181. Monoecious, oogonium single, oblong, oper- 

 culate, division superior; oospore ellipsoid, filling the inflated 

 median or lower part of the oogonium ; membrane smooth ; 

 antheridium i-3-celled, subepigynous, subhypogynous or scat- 

 tered, spermatozoids binate, division horizontal. 



veg. cell, 6-1 1 /tt diatn., 3-8 diam. long, 



oog., 23-26/4 ' 41-50 AC long. 



oos., 21-23 M " 30-33 M " 



anth. cell, 6-9 /* " 7-9 y. " 



Charleston, 111., Transeau. Europe. 



In Oe. gradllimum the oogonium somewhat resembles that in 

 this species, but. the former is smaller in all parts. 



82. OE. iivUNOiSENSE Transeau, 1914, p. 299, PI. XXI-X, 

 figs. 6-8. Dioecious, nannandrous, gynandrosporous ; oogonia 

 single, subglobose to oboviform-globose, pore median ; oospore 

 globose or subglobose, nearly filling the oogonium ; epispore 

 with 4-7 spiral ribs, uniting at poles, polar axis always trans- 

 verse to axis of the filament ; inner wall smooth ; suffultory cell 

 swollen; androsporangia i-5-celled ; basal cell elongate ; dwarf 

 males slightly curved, on suffultory cell ; antheridium exterior, 

 i-4-celled. 



veg. cell, 13-18 /j. diam., 6-8 diam. long, 



suff. cell, 32-40^4 " 1.5-2 " " 



oog., 51-60 n " 60-70 /i long, 



oos., 45-56 M " 48-66/14 " 



andr. cell, 13-17 M " 17-22 /u " 



nan. stipe, 14-17 M " 37-57 /* " 



anth. cell, 9-r2 M " 15-23 M " 



Lerna, 111., Transeau. 



83. OE. MACROSPORUM W. & G. S. West ex Him, 1900, p. 

 227, PI. XXXVIII, fig. 232. Dioecious, nannandrous ; oogo- 

 gonium single, subdepressed-globose, operculate, division 

 median, very narrow ; oospore subdepressed-globose, filling the 

 oogonium, membrane smooth ; dwarf males curved, on the 

 suffultory cell ; antheridium exterior, i-?-celled. 



veg. cell, !3-i3-5 M diam., 4-5 diam. long, 



oog., 44-46 n " 39-40 M long, 



nan., n-5 M " 38;* " 



Utica, Ohio, Transeau. England. 



The only nannandrous species with external antheridium and 

 median division of the oogonium. 



