Myxophyceae 133 



5-8 mic. in diameter, not constricted at joints; apical cell rotund or obtuse 

 conical; calyptra slightly thickened; cells S-ii mic. in length; transverse 

 ■walls usually inconspicuous, not granulated; cell contents granular, blue- 

 green. 



Massachusetts. On moist earth by roadside. Maiden. July 1904. (Col- 

 lins). New Jersey. On marsh bottoms. (Wolle). Pennsylvania. On 

 old logs partially submerged. (Wolle). Maryland. Forming tufts in an 

 old brickyard. Baltimore. November 1896. (Humphrey). Minnesota. On 

 trunk of tree-fern. University greenhouse. Minneapolis. November 1894. 

 (Tilden). Washington. Among mosses on damp ground. Newhall, Orcas 

 Island. (Gardner). California. In a greenhouse. Mount View Cemetery, 

 Oakland. July 1902. (Gardner). West Indies. (Maze and Schramm, 



Ramon de la Sagra). Bay Estate, Barbados. (Howard). 



Var. rivularis (Wolle) Tilden. American Algae. Cent. I. no. 67. 1894. 

 (L. phormidium rivularis Wolle). Wolle. Fresh-Water Algae U. 

 S. 299. 1887. De Toni. Syll. Algar. 5: 304. 1907. 



Johnson and Atwell. Fresh Water Algae. Northwestern University. 

 Report Dept. Nat. Hist. 21. 1890. Tilden. List of Fresh-Water Algae 

 collected in Minnesota during 1894. Minn. Bot. Studies, i: 235. 1895. 



Plant mass forming dirty aeruginous tufts 25 mm. long; filaments 

 10 mic. in diameter; cells 2.5-5 mic. in length; cell contents dark steel blue 

 or in portions yellowish green. 



Pennsylvania. River Lehigh, Bethlehem. (Wolle). Illinois. Running 

 water. Big Wood, Cook County. April. (Johnson and Atwell). Minne- 

 sota. Attached to stones in aquarium in Zoological laboratory. University 

 of Minnesota, Minneapolis. November 1894. (Tilden). 



Genus PORPHYROSIPHON Kuetzing. 

 Tab. Phyc. 2: 7. pi. 27. f. i. 1850-1852. 



Filaments unbranched; sheaths firm, solid, lamellose, usually purple 

 or flesh-colored; trichomes solitary within the sheath; apical cell not 

 capitate. 



257. Porphyrosiphon notarisii (Meneghini) Kuetzing. Tab. Phyc. 2: 7. pi. 

 27. f. I. 1850-1852. Gomont. Monogr. Oscill. 69. 1893. De Toni. Syll. 

 Algar. 5: 314. 1907. 



Tilden. American Algae. Cent. I. no. 65 b. 1894. Collins, Holden and 

 Setchell. Phyc. Bor.-Am. Fasc. 9. no. 402. 1898. West and West. A 

 Further Contribution to the Freshwater Algae of the West Indies. Journ. 

 Linn. Soc. Bot. 34: 288. 1898-1900. 



Plate V. fig. 55. 



Plant mass expanded, cushion-shaped, dark purple; filaments variously 

 curved, densely entangled; sheaths purple, often colorless at the apex, 

 sometimes showing layers of different colors, the outer ones colorless, 

 firm, finally becoming very thick, lamellose, with the apex tapering and 

 fibrillose; trichomes 8-19 mic. in diameter, usually constricted at joints; 



