Minnesota Algae 

 72 



transverse walls usually furnished with two rows of granules; cell con- 

 tents pale blue-green. 



Arctic Regions. Fresh water. 82° 27' lat. N. (Dickie). Greenland. 

 Western part, south of 61° lat. N. (Rosenvinge). Western part^ ^^"^fl^"" 

 and Jonsson). New Hampshire. On mosses. Mill Brook Shelburne. (Far- 

 low) Massachusetts. Newton. (Farlow). Maiden and Readmg. On rocks 

 and trunks of trees. (Collins). Rhode Island. Providence. (Lathrop). 

 New Jersey. In stagnant waters; frequent. (Wolle). (Collms). Connecti- 

 cut Bruce's Brook. October 1890; floating in pool below Factory Pond; 

 Housatonic River, on wall of quartz mill; Fresh Pond; Pequonnock River. 

 Bridgeport. (Holden). New York. In deep pool. Ithaca flats. April 189S. 

 (Atkinson). Pennsylvania. Dripping, mossy rocks, pools, margins of 

 pools or free swimming; in hot water. (Wolle). Ohio. In plankton. 

 Put-in-Bay, Lake Erie. (Snow). Indiana. "Thfee different species of 

 Oscillatoria appeared in considerable abundance in the ponds and 

 streams under observation. These were Oscillatoria tenuis, O. 

 limosa and O. p r i n c e p s. Some other species were noticed but they 

 did not persist any length of time. O. t e n u i s was the most abundant form 

 both in quantity and distribution. It was abundant in stream no. i. (Jor- 

 dan Branch), especially in the lower part, and in the smaller of the water- 

 works ponds during the greater part of the year. In stream no. i it grew 

 on the stones in the bottom, forming a tolerably dense stratum. A similar 

 stratum formed on the rocks at the outlet of pond no. 4 (Monon Pond) 

 v/henever sufficient water flowed over the spillway to keep them wet. 

 Around the edge of the smaller of the water-works ponds there was usually 

 a stratum covering the bottom in the shallow water. Whenever sufficient 

 oxygen collected in the meshes of a mass it was loosened and floated on 

 the surface." — Brown. Minnesota. Lining sides of tanks in Zoological 

 Laboratory, University of Minnesota, Minneapolis. November 1894. (Til- 

 den). In arm of Mississippi River (old channel). St. Paul Park. October 

 1897. (Freeman). Nebraska. Rocks, pools, margins of ponds, or floating 

 free; common throughout the state. (Saunders). Wyoming. In small 

 mountain spring in a bog, together with moss and water cress. Valley of 

 Nez Perces Creek, Lower Geyser Basin, Yellowstone National Park. June 

 T896. (Tilden). Washington. Floating in slightly brackish water in a 

 ditch. La Conner, Skagit County. (Gardner). "Agrees well with O. tenuis, 

 except that it is hardly at all torulose." — Setchell. West Indies. Guade- 

 loupe. (Maze and Schramm). Bath. July 1900. (Pease and Butler). 

 Var. natans (Kuetzing) Gomont. 1. c. 241. De Toni. 1. c. 168. 

 Wolle and Martindale. Algae. Catalogue of Plants found in New Jersey. 

 Geol. Surv. N. J. 2: 609. 1889. (O. natans Kg.). Tilden. American Al- 

 gae. Cent. I. no. 76. 1894; List of Fresh-water Algae collected in Minnesota 

 during 1894. Minn. Bot. Studies, i : 235. 1895. Snow. The Plankton Algae 

 cf Lake Erie. U. S. Fish Comm. Bull, for 1902. 22: 393. 1903. Collins. 

 Phycological Notes of the late Isaac Holden. — II. Rhodora. 7: 236. 1905. 

 Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 25. no. 1207. 1905; Fasc, 



