THE GREEN ALGAE OF NORTH AMERICA 275 



veg. cell, 19-25 M diam., 2^-3^ diam. long. 



oog., 46-56 fj. " 70-90 M long. 



andr. eel], 16-20 M " 9-25 M " 



nan. stipe, 16-19 M " 29-33 M " 



anth. cell, 10-13 n " 7-10 p. " 



Mass., N. J., Alaska. Europe, Australia. 



Var. RETICULATA (Nordst.) Him, 1900, p. 365, PI. L,XII, 

 fig. 384. Epispore reticulate-denticulate, with doubly dentate 

 longitudinal ridges, the teeth united to each other by transverse 

 ridges ; the longitudinal ridges more or less wavy and crooked, 

 sometimes anastomosing ; dimensions about the same as in the 

 type. 



The netted surface above described is sometimes found, bu 

 exceptionally and in less degree, on oospores of the type ; the 

 variety merely has it more marked and more generally. 

 Mass. Europe. 



19. B. MINOR A. Braun in Kiitzing, 1849, p. 422 ; Wolle, 

 1887, p. 101, PI. LXXXVII, fig. 7; Him, 1900, p. 369, PI. 

 IvXIII, fig. 390. Dioecious, nannandrous, gynandrosporous ; 

 oogonia subobloug-ellipsoid, erector more rarely patent, below 

 terminal setae, androsporangia, or more rarely vegetative cells ; 

 androsporangia epigynous, subepigynousor scattered, i-?-celled ; 

 dwarf males near or on the oogonium ; antheridium exterior, 

 i-4-celled. 



veg. cell, 18-25 M diam., 1/^-2 diam. long. 



oog., 32-42 fj. " 59-69 M long. 



andr. cell, 15-16 /x " 16-21 M " 



nan. stipe, 12-15 M " 22-24 <" " 



anth. cell, 6-10 M " 6-7 p. " 



N. J. Sweden. 



Family 6. CHAETOPHORACEAE. 



Fronds filamentous, except in a few doubtful forms, usually 

 much branched, sometimes united in disk-like expansions ; cells 

 uninucleate, with band- or disk-shaped chromatophore, often 

 somewhat divided or with projections ; with one, rarely more 

 pyrenoids ; hairs almost always present, but varying in charac- 

 ter ; asexual reproduction by 4-ciliate, in some cases biciliate 

 zoo.spores, by aplanospores, akinetes, and with special Palmella 

 and Schizomeris stages in many genera ; sexual reproduction 

 in many genera by gametes similar to the zoospores. 



This family includes both fresh water and marine forms, but 

 the larger part is fresh water. There is a great range in differ- 

 entiation between the extreme forms, and some forms are in- 



