THE GREEN AI.GAE OF NORTH AMERICA 269 



veg. cell, 17-20 /u diam. 2-3 '< diain. long. 



oog., 40-48 M " 31-40 M long. 



andr. cell, 11-13,1* " 7-12 fj. " 



nan., 9-10 /u. " 21-26 M " 



Greenland, Conn., Pa., Alaska. l\uropt\ Australia. 



Forma SUPRAMKDIANA (Wittr.) Hirn, 1900, p. 328, PI. IJI, 

 fitf- 335 I Wittr. and Norclst., Alg. Kxsicc., No. 509, in part. 

 Oogonia smaller, usually below the terminal setae ; dissepiment 

 of suffultory cells somewhat above the middle, rarely quite near 

 the middle ; androsporangia scattered. 



veg. cell, 17-20 fj. diam., 2-3 diam. long. 



oog., 40-45 n " 32-37 n long. 



anth. cell, 11-12 M " 7-11 M " 



nan., 9-10 n " 20-25/0. " 



Pa. 



A common species and variable ; the plants distributed as P. 

 B.-A., No. 973, have vegetative cells and oogonia somewhat 

 more slender than in the type. 



3. B. CRENUivATA Pringsheim, 1858, p. 72, PI. VI, fig. 4; 

 Wolle, 1887, p. 97, PI. IvXXXVI, fig. 4; Hirn, 1900, p. 331, 

 PI. LIU, fig. 337. Wittr. and Nordst., Alg. Exsicc., No. 602, 

 in part. Dioecious, nannandrous, gynandrosporous ; oogonia 

 subdepressed-globose, patent, below the terminal setae or the 

 androsporangia, rarely under vegetative cells ; dissepiment of 

 suffultory cells usually median or slightly lower ; epispore of 

 oospore distinctly pitted ; androsporangia epigynous or scat- 

 tered, i-5-celled ; dwarf males on oogonium or near it, antherid- 

 ium interior, stipe slightly curved, shorter than the antheridium. 



veg. cell, 16-20 fj. diam., 2-3^ diam. long, 



oog., 43-48 M " 35-43 M long, 



anth. cell, 10-15 n " 7- JO M " 



nan., 9-10 /u " 24-26 ,u " 



Europe, Australia. 



Quite doubtfully American, there being no authority other 

 than Wolle's description and figures. 



4. B. NORDSTEDTII Wittrock, 1874, p. 44; Hirn, 1900, p. 

 332, PI. LIU, fig. 340 ; P. B.-A., No. 717. Dioecious, nannan- 

 drous, gynandrosporous ; oogonia depressed sub-quadrangular- 

 globose or depressed-globose, patent, below the androsporangia, 

 or very rarely below the terminal setae ; dissepiment of sufful- 

 tory cells superior, rarely sub-median ; epispore of oospore finely 

 pitted or nearly smooth ; androsporangia i -celled, epigynous ; 

 dwarf males on oogonium ; antheridium interior, stipe slightly 

 curved, shorter than the antheridium. 



