292 Minnesota Algae 



Bot. VII. 4: 352. 1886. (R. biasolettiana Menegh.). De Toni. 

 Syll. Algar. 5: 667. 1907. 



Collins. Notes on New England Algae. Bull. Torr. Bot. Club. 9: 69. 

 1882. (Rivularia warreniae Thur.). Setchell. Notes on some 

 Cyanophyceae of New England. Bull. Torr. Bot. Club. 22: 427. 1895. 

 Tilden, American Algae. Cent. II. no. 166. 1896. Collins, Holden and 

 Setchell. Pliyc. Bor.-Am. Fasc. 8. no. 358. 1897. Tilden. List of Fresh- 

 Water Algae collected in Minnesota during 1896 and 1897. Minn. Bot. 

 Studies. 2: 27. 1898. Collins. Preliminary Lists of New England Plants. 

 — V. Marine Algae. Rhodora. 2: 43. 1900. Collins, Holden and Setchell. 

 Phyc. Bor.-Am. Fasc. 18. no. 860. 1901. Saunders. The Algae. Harriman 

 Alaska Expedition. Proc. Wash. Acad. Sci. 3: 399. 1901. Tilden. Ameri- 

 can Algae. Cent. VI. no. S7o. 1902. Setchell and Gardner. Algae of North- 

 western America. Univ. Calif. Pub. Bot. l: 198. 1903. 



Plate XX. fig. 16, 17. 



Colonies at first hemispherical, afterwards expanded into an olive or 

 blackish, gelatinous, crustaceous, cushion-like layer, 2^8 mm. in thickness, 

 indurated with calcium carbonate in the interior; filaments about 18 mic. 

 Ill diameter, approximate; sheaths wide, lamellose, colorless or yellowish, 

 or showing transverse zones, ocreate; ocreae dilated, funnel-shaped; trich- 

 omes 5-9 mic. in diameter, ending in a very thin, long, flexuous hair; lower 

 cells a little shorter than the diameter, the upper ones one-third as long as 

 broad; cell contents blue-green; heterocysts oblong, basal, one to three, 

 rarely intercalary. 



Alaska. On dripping rocks, on roots, etc., in fresh or brackish water. 

 West shore of Amaknak Island, Bay of Unalaska; at mouth of creek, Iliu- 

 liuk, Unalaska. (Setchell and Lawson). Forming minute, hard, dark bluish 

 green thalli, 1-3 mm. in diameter, which finally become agglutinated into 

 iiollow, indefinite masses. On rocks in freshwater streams. Juneau; Glacier 

 Bay. (Saunders). Canada. On sandstone rocks just above high tide, but 

 submerged or at least washed by waves during storms. Minnesota Seaside 

 Station, Port Renfrew, Vancouver Island, British Columbia. December 1901 

 (Tilden). New Hampshire. (Collins). Massachusetts. Growing on a 

 rock, above high water mark but where the spray formed little pools in 

 rough weather. Marblehead. September 1881; in moist places just above 

 high water mark. Marblehead. June 1901. (Collins). Rhode Island. (Col- 

 lins). Connecticut. Occurring in fairly typical form in perfectly fresh 

 water. Gardner's Lake. Eastern part of the state. (Setchell). South 

 Dakota. On rocks at edge of lake. Big Stone Lake. October 1895. (Grif- 

 fiths). Washington. East Sound, Orcas Island. (Gardner). California. 

 On dripping vertical faces of the cliff, just above high water mark. Carmel 

 Bay, Monterey County. December 1896. (Nott and Setchell). 



532. Rivularia bornetiana Setchell. Notes on some Cyanophyceae of New 

 England. Bull. Torr. Bot. Club. 22: 426. 1895. De Toni. Syll. Al- 

 gar. s: 666. 1907. 



Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 4. no. 157. 1896. 



