THE GREEN ALGAE OF NORTH AMERICA 109 



tate or serrate, making 1-3 turns in the cell ; fertile cells swollen 

 only oil the side of the conjugation ; cells in filament which 

 have not conjugated often much swollen and distorted; spores 

 ovoid or ellipsoid, i>^-2^' diam. long; diam. 33-38 p.. Me., 

 Mass., N. Y., X. J., Iowa, Wash., Cal. AVmyV, So. America. 

 A polymorphous species, but no other species of about the 

 same dimensions has the unilaterally inflated cells, and the ir- 

 regularly inflated vegetative cells. 



6. S. FUSCO-ATRA Rabenhorst, Algen, No. 98 ; Wolle, 1887, 

 p. 215, PI. CXL,, figs. 4-7. Filaments 40-45 /j. diam., cells 2-4 

 diam. long : cylindrical or slightly constricted at the nodes ; 

 becoming blackish with age, and purplish in the dried speci- 

 men ; chromatophore single, making 2-3 turns in the cell : 

 spores polymorphous, globose, ellipsoid, oblong or cylindrical, 

 40-47 (j. diam. Pa. 1 Europe. 



This species is included with some doubt ; the description by 

 Wolle is meager and the plate little more satisfactory ; no other 

 American record is known. No mention is made of the black- 

 ish or purplish brown color at maturity, from which it has its 

 name, and neither plate nor description indicates the collapsed 

 cells surrounding the ripe spores. The two-spired filament in 

 the figure is also suspicious. 



7. S. COMMUNIS (Hass.) Kiitzing, 1849, p. 439; Petit, 1880, 

 p. 16, PI. V, figs. 1-3 ; Wolle, 1887, p. 213, PI. CXLII, figs, i 

 and 2; P. B.-A., No. 1416. Filaments 20-25 /A diam., cells 3-5 

 diam. long; chromatophore single, quite slender, making 1^-4 

 turns in the cell ; fertile cells not at all swollen ; spores ellipsoid 

 with pointed ends, yellowish at maturity, 19-23 /A diam., 2-3 

 times as long. Mass., N. J. Europe, So. America. 



Often forming dense masses of dark green color in quiet 

 water ; soft to the touch but not mucilaginous ; best character- 

 ized by the uninflated fertile cells and by the long spores with 

 pointed ends. 



8. S. CONDENSATA (Vauch.) Kiitzing, 1843, p. 279; Petit, 

 1880, p. 22, PI. IX, figs. 6-8; Wolle, 1887, p. 215; Wittr. and 

 Nordst., Alg. Exsicc., No. 247. Filaments 48-54 /* diam., 

 cells as long as broad, or slightly longer or shorter ; chromato- 

 phore single, slender, with large pyrenoids making ^-i^ 

 turns in the cell ; fertile cell not inflated; spores ellipsoid, i^ 

 diam. long, up to 36 ^ diam., conjugation usually lateral. 



J-'.nropc, So. America. 



