46 SPECIES OF ALGiE. 



b. Filaments dividing longitudinally; mucous; 4 in. long, floating, 



Lenormandi, 138 



b. " not dividing longitudinally (c). 



c. Joints often constricted; diameter of cells 9-iOyU . rivularis, 136 

 c. Joints not constricted; aquatic; variable; diameter of cells 5-50/*, 



sub tilts, 135 



c. " " " " filaments tortuous, very long, 



muralis, 137 

 {. " " " On damp walls, pavements, exposed rocks, etc., (*) 

 *. Cells 6-7/^ in diameter; on walls, pavements, etc. . mitens, 137 

 *. " 7-9.5/t " " cell contents usually at one side; on ex- 



posed rocks, etc. . . . flaccida, 137 



d. Cells i2-i4/< in diameter . aqualis, 134 



d. Cells about ijx in diameter; on moist clay or sand . . varia, 138 



e. Green, cell contents usually on one side, hemispherical, flaccida, 137 

 e. Green, dark, bright or pale; contents diffused (/). 



/. Joints often constricted; cells 9-io/t in diameter . rivularis, 136 

 /. " not constricted; filaments attached, 17-25/^ in diameter, 



tenuis, 134 

 /. " " " filaments not attached {g). 



g. In brackish water, filaments 1-3 in. long, io-30/t dia., 



Younganum, 135 



g. In fresh water subtilis, 135 



h. Filaments dividing longitudinally, 4 in. long, floating, 



Lenormandi, 138 

 h. " not dividing (i). 



i. Joints often constricted, cells 9-iOyM in dia.. . rivularis, 136 



/. " not constricted in sterile filaments (7). 

 j. Filaments lofjL or more in diameter (K). 

 j. " less than loyu in diameter (m). 



k. In brackish water; filaments 20-30/* in dia. . Younganum, 135 

 k. In brackish and in fresh water; filaments 38-5o/< in dia., 



speciosa, 135 

 k. In fresh water only or on the ground (/). 



/. On shaded ground; flexuous, interwoven. . parietina,- 138 



/. Aquatic; filaments io-i2yU in dia. . . . oscillarina, i^y 



I. " " 14-40/i" " Zonata, 133 



m. Bright, grass green; filaments tortuous, very long, interwoven, 



muralis, 137 

 m. Yellowish green, mucous; cells shorter than wide . compacta, 1^6 



