248 Minnesota Algae 



rocks. Castle Bruce River (2,000-3,000 feet), Dominica. January, February 

 T896. (Elliott). Hawaii. In stagnant water. Mauna Kea, Hawaii. (Berg- 

 gren, Lemmermann). 



453. Stigonema minutum (Agardh) Hassall. History of the British Fresh- 

 water Algae. 1 : 230. pi. 67. f. 3, 4. 1845. Bornet and Flahault. Revis. 

 des Nostoc. Ann. Sci. Nat. Bot. VH. 5: 72. 1887. De Toni. Syll. 

 Algar. s: 582. 1907. 



Wood. Prodromus of a Study of the Freshwater Algae of Eastern 

 North America. 133. 1869; Contr. Hist. Fresh-Water Algae North America. 

 72, 74. pi. 9. f. 2. 1872. (Sirosiphon acervatus Wood, S. 1 i g n i c o- 

 la Wood). WoUe. Fresh-Water Algae U. S. 273. pi. 193. f. i-ii. 1887. 

 West and West. On some Freshwater Algae from the West Indies. Journ. 

 Linn. Soc. Bot. 30: 273. 189S; A Further Contribution to the Freshwater 

 Algae of the West Indies. 1. c. 34: 286. 1899. Collins, Holden and Setch- 

 ell. Phyc. Bor.-Am. Ease. 15. no. 713. 1900. Saunders. The Algae. Harri- 

 man Alaska Exped. Proc. Wash. Acad. Sci. 3: 399. 1901. Setchell and 

 Gardner. Algae of Northwestern America. Univ. Calif. Pub. Bot. i : 197. 1903. 

 Collins. Algae of the Flume. Rhodora. 6: 230. 1904; Phycological Notes of 

 the late Isaac Holden. — II. Rhodora. 7: 237. 1905. Lemmermann. Al- 

 genfi. Sandwich.-Inseln. Bot. Jahrb. 34: 627. 1905. 



Plate XV. fig. 18, 19. 



Plant mass crustaceous or cushion-like, thin, fragile, blackish; filaments 

 18-28 mic. in diameter, about i mm. in length, decumbent at the base, as- 

 cending, flexuously curved, branched, branches sometimes long, similar 

 to the primary filaments, sometimes very short, bearing hormogones, often 

 very much crowded on one side; sheaths yellowish or yellowish brown, 

 lamellose, the special envelope surrounding each cell frequently of a deep- 

 er color; trichomes in the basal portion of the filament usually consisting 

 of one row of cells, those in the middle and upper portions often composed 

 of two to four rows; heterocysts numerous, lateral or intercalary; hormo- 

 gones 12-15 rnic. in diameter 25-35 mic in length. 



Alaska. Forming a thin brown coating with Chroococcus rufes- 

 c e n s, on damp rocks, several hundred feet above sea level. Prince William 

 Sound. (Trelease). Greenland. (Borgesen). New Hampshire. One of 

 the species composing the brown coating on wall of the Flume. September 

 1904. (Collins). Massachusetts. On wet clifif. Cascade, Melrose. April 

 1900. (Collins). Connecticut. On submerged rocks in Plantain Pond, 

 Salisbury. October. (Holden). South Carolina. On old boards. April; on 

 boards over which spring water was constantly running, August; growing 

 on bark of Ilex opaca; on old wood and on trunks of trees. (Ravenel); 

 West Indies. On damp wall of dam. Sharp's River, St. Vincent; on trees, 

 summit of Trois Pitons (4500 feet); on lime-trees, Shanford Estate; in 

 stream, Wotten Waven, Dominica. (Elliott). Hawaii. On gravelly vol- 

 canic soil. Hilo, Hawaii. (Berggren, Schauinsland). 



Var. saxicola (Naegelii) Bornet and Flahault. 1. c. 73. De Toni. 1. 

 c. 584. 



