64 SPECIES OF ALG^E. 



86 SCYTONEMA. 



On warm sandy soil; blackish; diam. with sheath io-i4yu, 



thermale, 259 



On bark of trees, in small, olive green or brown tufts (a). 

 On old wet wood (b). 

 g On moist rocks, wall, earth, etc. (c). 

 Submerged in sweet water, (g}. 



g Floating in sweet water; diam. of filaments 12-20/4 . . natans, 251 

 i4-i8yw cincinnatiuti, 254 



| Brackish or salt; filaments curved and interwoven, chrysochlorum, 253 

 (i. Filaments bluish; branches forming long loops, ends continuous, 



niirabilis, 255 

 ft. Filaments creeping; branches not looped, ends not continuous, 



cortex, 256 



p. Diameter of filaments with sheath about 20;^ . . intertextum, 258 

 b. " " " " " 10-15;* . . simplice, 259 



& " " " " " 20-25/1 . . Heppii, 260 



f. Mpre or less cushion-like, may become confluent (d). 

 f. Forming a stratum (e). 



f. Tufted or turflike (/). 



(I. On pots etc. in conservatory; filaments bluish, sheath close, color- 

 less Castellii, 255 



d. On moist rocks, etc; sheath thick, often with a lime deposit, 



cine r cum, 258 



e. Diameter of sheath 25-33^, lamellate myochrous, 252 



e. Filaments flexuous, long, apices rounded; diam. 12-16-25^, 



cataracta, 252 

 e. <* entangled, branches mostly single; cell ends somewhat 



contracted gracile, 253 



e. Filaments interwoven, cells about as long as wide . turfosum, 253 

 e. M " sheath dissolving into fibrils, 



Not a rissii, 255 



/. Branches thinner, often ^ or less than the stem^tolypotrichoidcs, 250 

 /. Branches thinner at base only, quickly enlarging . Niegelii 252 



g. Filaments somewhat curved, branches thinner, bluish, 



calotrichoidcs, 25 1 

 I 



87 SYMPHYOSIPHON. 



. Diameter of filament without sheath j/j. or less (a). 



g. " " " " " more than yyw (/). 



