THE GREEN ALGAE OF NORTH AMERICA 255 



55. OE. CRASSIUSCULUM var. IDIOANDROSPORUM Wittr. and 

 Norclst., Alg. Exsicc., Nos. 208, 310; Wolle, 1887, p. 80, PL 

 LXXVII, figs. 14-19; Him, 1900, p. 215, PI. XXXV, fig. 

 220; P. B.-A., Nos. 72, 716. Dioecious, nannandrous, idioan- 

 drosporous ; oogonia single or 2, globose-oboviform to globose ; 

 oogonia ellipsoid-globose to angular-oboviform or angular-glo- 

 bose, nearly filling the oogonium ; pore superior; membrane 

 smooth, thick ; suffultory cell similar to the other vegetative 

 cells; androsporangia 2-5-celled ; dwarf males nearly straight, 

 on or near the suffultory cell ; antheridium exterior, i- (or 

 more- ?) celled. 



veg. cell, 25-36 /a diam., 2)^-5^ diam. long, 



oog., 48-59^ " 57-9 Mlong. 



oos., 42-57 M " 50-66 M " 



andr. cell, 30-34 /a " 12-21 /x " 



nan. stipe, 14-16 /x " 60-70 /x " 



anth. cell, 8-10 /x " 10-18 /x " 



Me., Mass., Conn., N. Y., N. J., Pa., Minn., So. Dakota. 



Northern Europe. 



The type, occurring in northern Europe, is gynandrosporous, 

 and never has the angular oospores. The plants from Maine 

 and Mass., distributed under No. 72, P. B.-A., have the 

 oospores and oogonia broader and more globose, often 4 in a 

 series ; the androsporangia are more slender. From the three 

 following species, resembling it in many particulars, Oe. crassi- 

 iisadum in all its forms can be distinguished by the unswollen 

 suffultor)- cell ; the unusually thick membrane is also to be 

 noted. 



56. OE. BORISIANUM (Led.) Wittrock, 1870, p. 132; 

 Wolle, 1887, p. 81, PI. LXXVIII, figs. 6-9; Him, 1900, p. 

 217, PI. XXXVI, fig. 223; P. B.-A., No. 517. Dioecious, 

 nannaudrous, gyuaudrosporous or idioandrosporous ; oogonia 

 single, or rarely 2-3, oboviform or quadrangular-ellipsoid, pore 

 superior; oospore ellipsoid or oboviform, sometimes quadrangu- 

 lar-ellipsoid, not quite filling the oogonium, membrane smooth ; 

 suffultory cell swollen ; androsporangia i-7-celled, in the upper 

 part of the filament, often subepigynous ; basal cell elongate; 

 terminal cell, which may be an oogonium, short-apiculate or 

 obtuse, or sometimes produced in a long, hyaline seta ; dwarf 

 males slightly curved, on suffultory cell ; antheridium exterior, 

 i-2-celled. 



