THE GREEN ALGAE OF NORTH AMERICA 269 



veg. cell, 17-20 fji diam. 2-3 '< diam. long. 



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



andr. cell, 11-13 M " 7- 12 M " 



nan., 9-10 /j. " 21-26 /j. " 



Greenland, Conn., Pa., Alaska. Europe, Australia. 



Forma SUPRAMEDIANA (Wittr.) Him, 1900, p. 328, PI. LIT, 

 % 335 ; Wittr. and Nordst., Alg. Exsicc., 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 M diam., 2-3 diam. long. 



oog., 40-45 M " 3 2 -37 M long. 



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



nan., 9-10 M " 20-25 /" " 



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. CRENULATA Pringsheini, 1858, p. 72, PI. VI, fig. 4; 

 Wolle, 1887, p. 97, PI. I.XXXVI, fig. 4; Him, 1900, p. 331, 

 PI. LIII, 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 M diam., 2-3^ diam. long. 



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



anth. cell, 10-15 /j. " 7-10 /j. " 



nan., 9-10 M " 24-26 .a " 



Europe, Austi'alia. 



Quite doubtfully American, there being no authority other 

 than Wolle's description and figures. 



4. B. NORDSTP;DTII Wittrock, 1874, p. 44; Him, 1900, p. 

 332, PI. LIII, 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; androsporaugia i -celled, epigyuous ; 

 dwarf males on oogonium ; antheridium interior, stipe slightly 

 curved, shorter than the antheridium. 



