THE GREEN ALGAE OP NORTH AMERICA 113 



Petit, iSSo, p. 32, PI. XII, figs. 3 and 4; Wolle, 1887, p. 219, 

 PI. CL,X, figs. 1-3; Phyk. Univ., No. 440. Filaments 150-160 

 /A diain., cells 1-2 diani. long ; chroma tophores numerous, rarely 

 as few as 4, often 10 ; not parallel, rather slender, sinuate at the 

 margin, with very small pyrenoids, making y 2 -i turn in the 

 cell, or sometimes nearly straight ; fertile cells not swollen ; 

 spores broadly ovoid and flattened, about i^ diam. long, diam. 

 140-150 /A. Mass., Pa., N. J., Iowa. Europe, So. America. 



The largest species of the genus, the individual filaments 

 quite distinct to the eye, firm and crisped, somewhat mucilagi- 

 nous. 



18. S. AFFINIS (Hass.) Petit, 1880, p. 18, PI. Ill, figs. 

 13-14 ; P. B.-A., No. 959. Filaments 27-30 /A diam., cells 1^-3 

 diam. long; chromatophore single, quite slender, making 1-3^ 

 turns in the cell, often forming only a single ring; fertile cells 

 much swollen, often nearly or quite spherical ; spores ellipsoid, 

 1-1^2 diam. long, up to 30 /A diam. Lateral conjugation more 

 common than scalariform. Jamaica, Alaska. Europe. 



Quite distinct by the uniformly short vegetative cells, and the 

 bullate fertile cells. 



19. S. MIRABILIS (Hass.) Ku'tzing, 1849, p. 438; Petit, 

 1880, p. 14, PI. Ill, figs. 3 and 4; Wolle, 1887, p. 211, PI. 

 CXXXIV, figs, i and 2; Wittr. and Nordst., Alg. Exsicc., 

 No. 1377. Filaments 24-27 ^ diam., cells 4-10 diam. long; 

 chromatophore single, quite broad, making 4-7 turns in the 

 cell ; fertile cells swollen, even before the formation of the 

 spores, which are ovoid or ellipsoid, 24-26 /u, diam., i l />-2 diam. 

 long ; and are formed without any observable conjugation, 

 either lateral or scalariform. Maine, Wis. Europe, Asia. 



The spores of this species, though in appearance like zygo- 

 spores, are more properly to be considered aplanospores. 



20. S. FLAVESCENS (Hass.) Kiitzing, 1849, p. 438 ; Petit, 

 1880, p. 15, PI. HI, figs. 5 and 6; Wolle, 1887, p. 211, PI. 

 CXXXIV, figs. 3 and 4 ; Rabenhorst, Algen Sachsens, No. 60. 

 Filaments 11-13 /A diam., cells 3-4 diam. long; chromatophore 

 single, quite broad, yellowish green, making 1-2 turns in the 

 cell ; fertile cells swollen ; spores ovoid with rounded ends, yel- 

 lowish when mature, 20 /A diam., i ^ diam. long. Florida. 



Europe. 



Possibly only a variety of the following species, from which it 

 differs chiefly in its smaller diameter, and in the different form 

 of the fertile cells. Wolle gives a larger diameter for the fila- 



