SPECIES OF ALG/E. 65 



a. Diameter of filaments 2-3//, of sheath at the base 6-7/^, apex 3-4// 



crustaceus, 263 



a. " " " 5-7/^ . ambiguum, 262 



b. Surface pubescent; black; filaments 9-15/* . . Castelli, 262 



b. " " filaments i5-20yu . Aiistinii, 262 

 (5. Surface not pubescent (^). 



c. Diameter of filaments 15/i or less {d). 



d. Filaments brown, 12-15/Y, cells j^ as long as wide, 



Bornetianum, 261 

 d. " bluish, 8-io/A, cells about as long as wide hirtubis, 261 



d. " bluish, 8-12/^, sheath wider at base Hofmanni, 262 



88. TOLYPOTHRIX. 



§ On tree trunks, surface velvety, blackish; diam. ii-i4yM, 



trimcicola, 266 



§ On wet exposed rocks {a). 



§ Aquatic (U). 



a. Reddish brown; filaments with dark transverse bands, 



Ravenellii, 265 



a. Red, purple and black; filaments much branched . rupestris, 265 



b. Spherical, pea-like masses, filaments bluish , yEgagrophila, 264 



b. Not spherical masses (c). 



c. Diameter of filaments 3-4/U . . . . . , tenuis, 265, 

 c. Diameter 10-17/^ (d). 



c. " 9-11;^, often interrupted by inclined disc-like cells, 



muscicola, 264 



d. Impossible to separate here, distorta, 26y, ptikhra, 26^; flaccida, 265 



89. PLECTONEMA. 



One species . . . . mirabile, 266 



90. PETALONE.MA. 



One species . . . alatiun^ 267 



91. SIROSIPHON. 



§ Aquatic; brown; cells of stems 2-rowed, in branches i-rowed, 



ocellatus, 272 



§ On old wood and tree trunks; in black spots; often aggregated, 



lignicola, 273 



§ In soda springs, west; not fully described . Brandegeei, 274 



§ On damp soil or wet rocks (a). 



