SPECIES OF ALG^. 



/. Diameter 30yU or more (m). 

 " less than 30// (n). 



m. Cells :^ to ^ as long as wide; diam. 30-45// 

 m. Cells about \ as long as wide . 

 n. Diameter less than 19/t (0). 

 n. " ipyu or more (/). 



o. Diameter 15/i; cells /^-/^ as long as wide 

 0. " io-i8/<; variable 



/. Diameter 19-22//; cells Yi-yi as long as wide 

 p. " ,23-28/i; cells |-|- " " " " . 



71 



princeps, 2>'^1 

 imperator, 317 



. per cur sa, 315 



Frxlichii, 315 



major, 316 



Bonnemasotiit, 316 



105. BEGGIATOA. 



«. Diameter of filaments 1-1.5/i 

 «. " " " 1. 8-2.5// 



niveicm, 318 

 leptom itiformis, 319 



106. 



LEPTOTHRIX. 



^. 



In hot waste water, waving, 6 mm thick hinmilia, 320 



On old wet walls; filaments strongly curved . calcicola, 319 



On wet wood, herbaceous green; diam. 1.8-2.25// herbacea, 320 



Aquatic, sometimes on wet rocks {a). 

 Forming spherical masses, light yellowish, tough, hollow, 4-8 mm 



diam . . ... bullosa, 321 



Forming cloud-like, floating fragile masses, yellowish; filaments 

 about 2// diam. . . ochracea, 322 



Forming a stratum (V). 

 Forming a tuft (e). 

 Filaments 3// or more in diam. -. tenax, 



" less than 3// in diam. {/). 



Stratum composed of clusters, light bluish . rigidula, 



" more or less expanded [d). 

 Bluish or greenish above, yellowish or colorless below, 



laminosa, 

 Bright bluish, thin, membranaceous . ceruginea. 



Bluish, becoming yellowish . . ccespitosa, 320 



Purple green or amethyst . . tinctoria, 321 



319 



321 



321 

 319 



I06fl. ASTEROTHRIX. 



One species 



Creginii, 322 



