222 Minnesota Algae 



Algologiques. 146. 1880. Bornet and Flahault. Revis. des Nostoc. 

 Ann. Sci. Nat. Bot. VII. 5: 92. 1887. De Toni. Syll. Algar. 5: 

 503. 1907. 

 Maze and Schramm. Essai Class. Algues Guadeloupe. 34. 1870-1877. 

 (S. cyanescens Crouan). 



Plate XII. fig. 13, 14- 



Plant mass cushion-shaped, woolly, widely expanded, blackish violet 

 or becoming reddish; filaments 16-30 mic. in diameter, 5-10 mm. long, 

 free, branched; false branches approximate, solitary or in pairs; sheaths 

 thick, gelatinous; trichomes 12-18 mic. in diameter; cells somewhat quad- 

 rate or two or three times shorter than their diameter; heterocysts equal- 

 ling the cells in diameter; cell contents olive or violet. 



West Indies. (Maze). 



40Q. Scytonema tolypotrichoides Kuetzing. Spec. Algar. 307. 1849. Bornet 

 and Flahault. Revis. des Nostoc. Ann. Sci. Nat. Bot. VII. 5: 100. 

 1887. De Toni. Syll. Algar. 5: 516. 1907. 

 Wood. Contr. Hist. Fresh-Water Algae North America. 61. pi. 6. f. 2. 



1872. (S. calotrichoides Wood). WoUe. Fresh Water Algae. II. 



Bull. Torr. Bot. Club. 6: 139. 1877; Fresh-Water Algae U. S. 250. pi. 182. 



f. 4-1 1. 1887. WoUe and Martindale. Algae. Britton's Catalogue of 



Plants found in New Jersey. Geol. Surv. N. J. 2: 604. 1889. Setchell. 



Notes on Cyanophyceae. — II. Erythea. 4: 192. 1896. 



Plate XIII. fig. I. 



Plant mass caespitose, floating, spherical, one cm. in diameter, brown 

 or green in color, filaments 10-15 mic. in diameter, 5-6 mm. long, radiating 

 from the center, repeatedly branched; sheaths colorless, becoming orange 

 brown, lamellose; the outer layers often colorless; trichomes 8-12 mic. in 

 diameter; cells somewhat quadrate or oblong, scarcely distinct; heterocysts 

 varied, some short, some long, rose-colored; cell contents densely granu- 

 lar, olive or yellowish. 



New York. In gelatinous masses on dripping rocks. Niagara Falls; 

 on wet or moist earth on the banks of rivers. (Wolle). New Jersey. 



Frequent on wet rocks. (Wolle). South Carolina. In wet, boggy places, 

 on rotten pine boards. September 1869. (Ravenel). 



410. Scytonema flavo-viride (Kuetzing) Bornet and Flahault. Revis. des 



Nostoc. Ann. Sci. Nat. Bot. VII. 5: loi. 1887. De Toni. Syll. Algar. 

 S: 517- 1907. 



Plant mass caespitose, entangled, floating, yellowish green; filaments 

 12-18 mic. in diameter, 2 cm. and more in length, rigid, very sparingly 

 branched; sheaths colorless, thick, lamellose; trichomes 6-10 mic. in di- 

 ameter, cylindrical, equal, constricted at joints; cells twice as long as wide, 

 sometimes up to 15 mic. in diameter and shorter than the diameter; hetero- 

 cysts quadrate or oblong, colorless; hormogones very long; cell contents 

 blue-green. 



Mexico. In swamps. Near Vera Cruz. (Miller). 



411. Scytonema mirabile (Dillwyn) Bornet. Les Nostocacees heterocystees 



du Systema Algarum de C. Agardh (1824) et leur Synonymie ac- 



