140 Minnesota Algae 



Plate VI. fig. 1-4. 



Plant mass not encrusted with calcium carbonate, somewhat gelatinous, 

 very hard when dry, papery-membranaceous, black or rarely yellowish 

 blue-green; filaments short, very much twisted and entangled, rarely 

 branched; sheaths firm, somewhat cartilaginous, tapering at the apex, at 

 first somewhat close, cylindrical, enclosing one trichome, later becoming 

 thicker, somewhat lamellose, irregular and roughened in outline, en- 

 closing two or rarely many trichomes; trichomes 1-1.7 mic. in diameter, 

 not constricted at joints; cells 2-6 mic. in length; transverse walls some- 

 times marked by two protoplasmic granules; cell contents pale blue-green. 



Massachusetts. On walls of greenhouse. Botanic Garden, Cambridge. 

 January 1899. (Collins). Nebraska. In greenhouse at the University. 

 (Saunders). Montana. Common everywhere all the year, on damp or 

 dripping rocks. (Anderson and Kelsey). Wyoming. Together with 



Synechococcus aeruginosus and Gloeocapsa violacea, 

 forming black "stalactites,"' 1-1.5 dm. long and .5 dm. in diameter, or ser- 

 rated, suspended masses or extended sheets. These hung from the top 

 and lined the walls of a small cave in which was the vent of a hot spring. 

 At short intervals they received jets of steam and a spray of hot water. Val- 

 ley of Nez Perces Creek, Lower Geyser Basin, Yellowstone National 

 Park. June 1896. (Tilden). 



267. Hypheothrix (?) hinnulea (Wolle). De Toni. Syll. Algar. 5: 336. 1907. 



WoUe. Fresh Water Algae. III. Bull. Torr. Bot. Club. 6: 182. 1877. 

 (Beggiatoa hinnulea Wolle) ; Fresh-Water Algae U. S. 320. pi. 

 208. f. s. 1887. Tilden. American Algae. Cent. I. no. 69. 1894. (L y n g b y a 

 hinnulea (Wolle) (Tilden) ; List of fresh-water Algae collected in Min- 

 nesota during 1894. Minn. Bot. Studies, i: 235. 1895. 



Plant mass flocculent, caespitose, waving, 6 mm. in thickness, light 

 fawn-colored; filaments 1.2-1.8 mic. in diameter, lo-is mm. in length, 

 flexible and contractile; sheaths' inconspicuous; transverse walls not visible; 

 cell contents colorless or light yellowish brown. 



Pennsylvania. In trenches for warm waste water from steam engines. 

 (Wolle). Minnesota. Collected in masses around the inlet pipe in tanks 

 in Zoological laboratory. University of Minnesota, Minneapolis. Novem- 

 ber 1894. (Tilden). 



268. Hypheothrix gloeophila (Kuetzing) Rabenhorst. Fl. Eur. Algar. 2: "JT. 



1865. De Toni. Syll. Algar. 5: 331. 1907. 



Plant mass forming a small mat; filaments 1.5-2 mic. in diameter, some- 

 times solitary, usually slightly curved and entangled; sheaths closely ad- 

 herent, entirely diffluent; cells once and a half longer than their diameter; 

 cell contents pale, almost colorless. 



Greenland. (Richter). 



269. Hypheothrix herbacea Kuetzing. Phyc. Gen. 199. 1843. De Toni. 



Syll. Algar. 5: 328. 1907. 



