Myxophyceae 249 



Nordstedt. De Algis Aquae Dulcis et de Characeis ex Insulis Sandvicen- 

 sibus a Sv. Berggren 187S reportatis. 7. 1878. (Sirosiphon saxicola 

 Naeg.). Farlow. Notes on the Cryptogamic Flora of the White Moun- 

 tains. Appalachia. 3 : 236. 1883. Wittrock and Nordstedt. Algae Aq. Dulc. 

 Exsicc. no. 669. 1884. 



Plant mass usually thin, crustaceous; filaments 15-21 raic. in diameter; 

 aheaths brown or brownish yellow; cells usually compressed, spherical in 

 the primary filaments, short and often dense in the branches, in the apex 

 truncate and forming a single row. 



New Hampshire. On exposed rocks and on Stereocaulon. 

 Top of Cabot Mountain, Shelburne. (Farlow). Pennsylvania. (Wolle). 



Hawaii. On gravelly volcanic soil. Hilo, Hawaii. (Berggren) 



454. Stigonema turfaceum (Berkeley) Cooke. British Fresh-Water Algae 



272. pi. III. f. 2. 1882-1884. Bornet and Flahault. Revis. des Nostoc. 



Ann. Sci. Nat. Bot. VII. 5: 74. 1887. De Toni. Syll. Algar. 5: 584. 



1907. 

 Wood. Contr. Hist. Fresh-Water Algae North America. 75. 1872. 

 (Sirosiphon pulvinatus Breb.). West. The Freshwater Algae 

 of Maine. Journ. of Bot. 27:207. 1889. Richter. Siisswasseralgen aus dem 

 Umanakdistrikt. Bib. Bot. 7: Heft. 42. 4. 1897. 



Plate XV. fig. 20. 



Plant mass cushion-like,, deep olivaceous black; filaments 27-37 niic. 

 in diameter, up to i mm. in length, decumbent at the base, ascending, vari- 

 ously curved, much branched; branches resembling the primary filament, 

 erect, bearing hormogones at the apex; sheaths thick, lamellose, yellowish 

 brown; trichomes consisting of from two to four rows of cells; heterocysts 

 collateral; hormogones 12 mic. in diameter, 45 mic. in length. 



Greenland. East coast. Summers of 1892 and 1893. (Vanhoflfen). 

 Maine. (West). New Jersey. Growing on exposed face of rocks. (Aus- 



tin). Pennsylvania. On rocks. Near Philadelphia. (Wood). 



Var. parvus Wood. Contr. Hist. Fresh-Water Algae North America. 

 75. pi. 10. f. I. 1872. De Toni. 1. c. 585. 



Filaments closely interwoven into a deep olive black, turfy mass, very 

 thick, irregularly and frequently branched, yellowish brown; branches poly- 

 morphous, their apices usually obtusely rounded, containing from one to 

 four rows of cells; sheaths thick, light yellowish brown, sometimes color- 

 less; trichomes consisting usually of several row of cells, cell contents gran- 

 ular, usually deep brown, sometimes light green. 



Pennsylvania. On the face of dripping rocks along the Wissahickon 

 Creek, near Philadelphia. (Hunt). 



455. Stigonema informe Kuetzing. Spec. Algar. 319. 1849. Bornet and 



Flahault. Revis. des Nostoc. VII. 5: 75. 1887. De Toni. Syll. Algar. 

 5: 585. 1907. 

 Wood. Contr. Hist. Fresh-Water Algae North America. 73. pi. 8. f. 4. 

 3872. (Sirosiphon guttula Wood). Wolle. Fresh Water Algae. III. 



