2/0 Minnesota Algae 



Metropolitan Park Commission, Meissachusetts. 127. 1896. Richter. Siiss- 

 v/asseralgen aus dem Umanakdistrikt. Bib. Bot. 7: Heft. 42. 4. 1897. Til- 

 den. List of Fresh-Water Algae collected in Minnesota during 1896 and 

 1897. Minn. Bot. Studies. 2: 27. 1898. Setchell. Notes on Cyanophyceae. 

 III. Erythea. 7: 45. 1899. Setchell and Gardner. Algae of Northwestern 

 America. Univ. Calif. Pub. Bot. i: 198. 1903. Collins. Phycological Notes 

 of the late Isaac Holden. — II. Rhodora. 7: 237. 1905. Collins, Holden 

 and Setchell. Phyc. Bor.-Am. Fasc. 28. no. 1360. 1907. Brown. Algal 

 Periodicity in certain Ponds and' Streams. Bull. Torr. Bot. Club. 35: 243, 

 248. 1908. Buchanan. Notes on the Algae of Iowa. Proc. Iowa Acad. 

 Sci. 14: 15. 1908. 



Plate XVIII. fig. 12. 



Filaments 10-12 mic. in diameter, up to I mm. in length, scattered or 

 aggregated into a crustaceous, thin, brown or black mass, erect or de- 

 cumbent, flexuously contorted, uniform or somewhat thicker at the base; 

 sheaths close, somewhat thick, yellowish brown, opaque, fragile, sometimes 

 uniform, sometimes ocreate; ocreae wide and fringed in upper portions; 

 trichomes 5-10 mic. in diameter, ending in a thin hair i mic. in diameter; 

 cells short, two or three times wider than long; heterocysts a little wider at 

 the base, intercalary heterocysts rare; hormogones few in the sheath, 

 three times longer than wide. 



Alaska. Forming reddish brown patches on dripping rocks. Amaknak 

 Cave, Amaknak Island, Bay of Unalaska. (Setchell and Lawson). Green- 

 land. Ij'manak. (Richter). Vermont. Northern part. (Wolle). Massa- 

 chusetts. In Nobska Pond, near Wood's Hole. (Farlow). Forming minute 

 tufts on rocks near Bear's Den, Middlesex Fells. (Collins). Rhode Island. 

 Forming a calcareous incrustation on perpendicular walls of a limestone 

 quarry. Lincoln. April 1906. (Collins). Connecticut. On stone dam of 

 Factory Pond; on dripping rocks between Canaan and Twin Lakes, Salis- 

 bury; on dripping rock, East Rock, New Haven; on sandy ground, shore 

 of Fresh Pond, October, November; forming a close coating on stone work 

 of dam, Pequonnock River, Bridgeport, October 1892. (Holden). New 

 Jersey. On submerged stones in shallow water. (Wolle). Indiana. Abun- 

 dant on stones in Stone Spring Branch the entire year. Bloomington. 

 (Brown). Minnesota. Growing in damp sand in stone quarry. Minne- 

 apolis. August 1894. (Anderson). On stone sides of fountain. Kenwood, 

 Minneapolis. August 1895. (Tilden). Iowa. On stem of Phragmites. 

 Ontario. (Buchanan). Colorado. Wet rorcks. Cannon City. (Brandegee). 

 California. On the sides of a water trough near Berkeley. July 1905. (Oster- 

 hout and Gardner). On clay bank of a small stream. North Berkeley. Sep- 

 tember 190S; on the sides of a water tank, Berkeley, February 1906. (Gard- 

 ner). 



Dr. Setchell considers the specimen under the name of Calothrix 

 1 h e r m a 1 i s, in Tilden. Am. Alg. no. 287, to belong to C. p a r i e t i n a. 

 This scarcely seems possible. 



"C. p a r i e t i n a may be entirely free from incrustation, or it may be 

 very thoroughly incrusted with either lime or silica. It is seldom, if ever, 

 branched, but the hormogonia in the incrusted specimens attach themselves 



