174 Minnesota Algae 



i8: 144. 1891. West and West. On some Freshwater Algae from the 

 West Indies. Journ. Linn. Soc. Bot. 30: 269. 1895. Collins. Algae. Flora 

 of the Blue Hills, Middlesex Fells, Stony Brook and Beaver Brook Reser- 

 vations of the Metropolitan Park Commission, Massachusetts. 128. 1896. 

 Tilden. American Algae. Cent. III. no. 291. 1898. Collins, Holden and 



Setchell. Phyc. Bor.-Am. Fasc. 16. no. 755. igoo. Bessey, Pound and 

 Clements. Additions to the Reported Flora of the State. Bot. Surv. Ne- 

 braska. 5: 12. 1901. Tilden. American Algae. Cent. VI. no. 582. 1902. 

 Setchell and Gardner. Algae of Northwestern America. Univ. Calif. Pub. 

 Bot. i: 191. 1903. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 

 30. no. 1453. 1908. Buchanan. Notes on the Algae of Iowa. Proc. Iowa. 

 Acad. Sci. 14: 11. igo8. 



Plate VIII. fig. 2. 



Colonies free, spherical 1-15 mm. in diameter, finally becoming ir- 

 regularly plicate-tuberculate, thick, sometimes 6-7 cm. in diameter, solid, 

 surrounded by a firm outer layer, olive green, yellowish or violet, be- 

 coming brownish; filaments flexuous, densely entangled; trichomes 4 rarely 



5 mic. in diameter; cells spherical compressed or barrel-shaped; heterocysts 



6 mic. in diameter, somewhat spherical; gonidia 5 mic. in diaineter, 7 mic. 

 in length, oval; wall of gonidium thick, smooth, becoming brownish. 



Alaska. On dripping rocks among mosses. Amaknak Island, Bay of 

 Unalaska. (Setchell and Lawsonj. Maine. Minute colonies free, among 

 various algae, in salt marsh pools. Harpswell. July 1905. (Collins). 

 Massachusetts. In minute blackish or greenish rounded masses on wet 

 rocks, near the Cascade. Melrose, Middlesex Fells. (Collins). Rhode 

 Island. Providence. (Bennett). New Jersey. Abundant on wet rocks. 

 (Wolle). Pennsylvania. Adhering to mosses and twigs in the water. 

 Spring Mills, near Philadelphia. (Wood). North Carolina. On wet rocks 

 with moss. Tryon. March 1897. (Green). Michigan. Grosse Isle. Near 

 mouth of the Detroit River. Summer of 1885. (Campbell). Minnesota. 

 Among mosses on cliff overhanging stream. Dalles of the St. Louis River, 

 Fond du Lac, near Duluth. August 1901. (Tilden). Iowa. Iowa City. 

 (Hobby). Ames. (Bessey). Nebraska. On soil in greenhouse. Lincoln. 

 (Bessey). Montana. Damp rocks in shady ravines. (Anderson and Kel- 

 sey). West Indies. On damp wall of dam in Sharp's River, St. Vincent. 

 May 1892.' (Elliott). 



326. Nostoc minutum Desmazieres. Plantes Cryptog. de France, ist Ed. 

 Fasc. II. no. 50. 1831. Bornet and Flahault. Revis. des Nostoc. 

 Ann. Sci. Nat. Bot. VII. 7: 209. 1888. De Toni. Syll. Algar. S: 4ii. 

 1907. 



Setchell and Gardner. Algae of Northwestern America. Univ. Calif. 

 Pub. Bot. i: 191, 1903. 



Plant mass minute, gregarious, spherical, finally becoming flattened, 

 membranaceous, up to 10 mm. in diameter; filaments densely entangled; 

 trichomes 2.5-3 ™'c. in diameter; cells barrel-shaped; heterocysts 4-5 mic. 

 in diameter; gonidia unknown. 



