i>20 Minnesota Algae 



rarely brownish, the external layers sometimes diffluent into colorless 

 fibrils; trichomes 12-16 mic. in diameter, here and there irregularly con- 

 stricted at joints; cells equal to or a little longer than their diameter; 

 heterocysts oblong or somewhat spherical, very pale brown in color, soli- 

 tary or in pairs at the base of the false branches; cell contents granular. 

 Florida. On old wood. (Smith). 



403. Scytonema austinii Wood. Contr. Hist. Fresh-Water Algae North 

 America. 58. 1874. De Toni. Syll. Algar. 5: 511. 1907. 

 WoUe. Fresh-Water Algae U. S. 261. pi. 189. f. 5. 1887. (S y ip p h y o- 

 siphon austinii Wood). WoUe and Martindale. Algae. Britton's 

 Catalogue of Plants found in New Jersey. Geol. Surv. N. J. 2: 605. 1889. 



Plant mass cushion-shaped and somewhat turfy, brown or black; fila- 

 ments 15-20 mic. in diameter, ascending, mostly unbranched, curved; sheaths 

 reddish or yellowish brown at the apex, colorless and transparent, firm, 

 indistinctly lamellose, with rough surface; trichomes 4-10 mic. in diame- 

 ter, blue-green or dark-colored, often very much thickened at the ends; cells 

 shorter or longer than their diameter; heterocysts short, cylindrical, some- 

 what quadrate or spherical, sometimes strongly compressed and much 

 shorter than broad. 



New Jersey. Forming a sort of miniature turfy cushion upon the rocks. 

 Little Falls. (Austin). Pennsylvania. On rocks. (Wolle) 



404. Scytonema millei Bornet in Bornet and Thuret. Notes Algologiques. 



147. 1880. Bornet and Flahault. Ann. Sci. Nat. Bot. VII. 5: 93. 

 1887. De Toni. Syll. Algar. 5: 505. 1907. 



Hohenacker. Algae Marinae Siccatae. no. 458. 1862. (S. 1 e p r i e u r i i 

 Kg.). Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 29. no. 1405. 

 J907. 



Plant mass cushion-shaped, woolly, widely expanded, 1-5 mm. thick, 

 dark green, becoming brown; filaments 15-21 mic. in diameter, flexuous, 

 entangled, branched; false branches erect, spreading; sheaths firm, brown- 

 ish; trichomes 10-15 ™ic. in diameter; cells compressed; heterocysts com- 

 pressed, brown, shorter than the diameter of the trichome. 



West Indies. On earth. St. Thomas. (Hohenacker). On earth and rocks. 

 Mavis Bank Road, Jamaica. June 1906. (Lewis). 



405. Scj^onema guyanense (Montagne) Bornet and Flahault. Revis. des 



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



506. 1907. 

 Montagne. Histoire de I'lle de Cuba. 10. pi. 2. f. 2. 1838. (S. b y s- 

 soid,eum corticale Mont.). Wood. Prodromus of a Study of the 

 Fresh- Water Algae of Eastern North America. Proc. Am. Phil. Soc. 11: 

 130. 1869. Maze and Schramm. Essai Class. Algues Guadeloupe. 33: 1870- 

 77. (Calothrix indica Crouan). Wood. Contr. Hist. Fresh- Water 

 Algae North America. 64. pi. 5. f. 4. 1872. (S. r a v e n e 1 i i Wood). Wood. 

 Fresh Water Algae. II. Bull. Torr. Bot. Club. 6: 139. 1877. (Symphyo- 

 siphon wollei Born.). Nordstedt. De Algis Aquae Dulcis et de 

 Characeis ex insulis Sandvicensibus a Sv. Berggren 1875 reportatis. (S. 



