64 SPECIES OF ALG^. 



86 SCYTONEMA. 



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



thermak, 259 

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

 § On old wet wood {b). 

 § On moist rocks, wall, earth, etc. {c). 

 § Submerged in sweet water, [g). 



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

 § " " " " " " " i4-i8yu cincinnatum, 254 



§ Brackish or salt; filaments curved and interwoven, f>4ryj-^<:,4/(?r«»?, 253 

 a. Filaments bluish; branches forming long loops, ends continuous, 



mirabilis, 255 



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



cortex, 256 



b. Diameter of filaments with sheath about 2o/< . . intertextuni, 258 

 b. " " " " " " io-15/f . . simplice, 259 



b. " " " " " " 20-25/^ . . Heppii, 260 



c. More or less cushion-like, may become confluent (d). 

 c. Forming a stratum {e). 



c. Tufted or turflike (/). 



d. 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, 



cinereum, 258 



e. Diameter of sheath 25-33/1, lamellate .... myochrous, 252 

 e. Filaments flexuous, long, apices rounded; diam. i2-i6-25/(, 



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. " " sheath dissolving into fibrils, 



Notarissii, 255 

 /. Branches thianer, often JS4 or less than the st&m,tolypotrichoides, 250 



f. Branches thinner at base only, quickly enlarging . Ncegelii 252 



g. Filaments somewhat curved, branches thinner, bluish, 



calotrichoides, 251 



87 SYMPHYOSIPHON. 



§. Diameter of filament without sheath 7/^ or less (a). 



§. " " " " " more than 7// {b). 



