IQO Minnesota Algae 



stituents of the plankton of many of our lakes at some seasons of the 

 j'ear. Occurs frequently in the sloughs in the northern part of the 

 state also." Jenning's Pond, near Boone River; slough, Eagle Grove, 1904. 

 (Buchanan). Nebraska. Free-swimming, membranaceous, blue-green. 



(Saunders). Washington. Floating in great abundance on quiet water. 

 Lake Union, Seattle. (Gardner). Central America. Very common in all 

 the phyto-plankton from Lake Amatitlan, Guatemala. Winter of 1905-1906. 

 (Meek). Very abundant, collected with a surface net. Lake Amatitlan. 

 Temperature of water TZ° ■ January 1906. (Kellerman, Meek and Smith). 



Var. treleasei Bornet and Flahault. 1. c. 230. De Toni. 1. c. 443. 



Trelease. The "Working'' of the Madison Lakes. Trans. Wis. Acad. 

 Sci. Arts and Letters. 123. pi. 10. f. 5. 1889. (A. mendotae Trelease). 



Cells 4 mic. in diameter; heterocysts 5 mic. in diameter, 10 mic. in 

 length; gonidia 6 mic. in diameter, 40 mic. in length, slightly curved. 



Wisconsin. Forming a copious water bloom on Lake Mendota, at Madi- 

 son, especially abundant in the fall. (Farlow). 



351. Anabaena circinalis Rabenhorst. Alg. Eur. Exsicc. no. 209. 1852. 



Bornet and Flahault. Revis. des Nostoc. Ann. Sci. Nat. Hot. VIL 



7: 230. 1888. De Toni. Syll. Algar. 5: 443- 1907. 

 Wood. Contr. Hist. Fresh-Water Algae North America. 38. pi. 3. f. 

 5. 1874. (A. gigantea Wood). Farlow. Notes on Fresh- Water Algae. 

 Bot. Gaz. 8: 225. 1883. (A. flos-aquae circinalis Kirchn.). Arthur. 

 Some Algae of Minnesota supposed to be Poisonous. Bull. Minn. Acad. 

 Nat. Sci. 2: (App.) 1-12. 1883. Bennett. Plants of Rhode Island. 114. 

 1888. Saunders. Protophyta-Phycophyta. Flora of Nebraska. 18. pi. i. 

 f. 12. 1894. Tilden. List of Fresh-Water Algae collected in Minnesota 

 during 1894. Minn. Bot. Studies, i: 236. 1895. Jackson and EUms. On 

 Odors and Tastes of Surface Waters, with Special Reference to Anabaena, 

 a Microscopical Organism found in Certain Water Supplies of Massachu- 

 setts. Review Am. Chem. Research. 8: 410. 1897. Nelson. Observations 

 upon some Algae which cause "Water Bloom." Minn. Bot. Studies. 3: 56. 

 pi. 14. f. 2. 1903. Moore and Kellerman. A Method of Destroying or Pre- 

 venting the Growth of Algae and Certain Pathogenic Bacteria in Water 

 Supplies. U. S. Dept. Agric. Bureau of Plant Industry. Bull. 64. 20. 1904. 

 Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 27. no. 1308. 1906. 

 Buchanan. Notes on the Algae of Iowa. Proc. Iowa Acad. Sci. 14: 12. 1908. 



Plate IX. fig. IS. 



Plant mass frothy; sheaths often not present; trichomes 8-14 mic. in 

 diameter, usually circinate, sometimes straight; cells a little shorter than 

 the diameter, spherical compressed; heterocysts 8-10 mic. in diameter, 

 somewhat spherical; gonidia 16-18 mic. in diameter, up to 30 mic. in length, 

 curved, oblique or cylindrical, the younger ones somewhat spherical, usually 

 remote from the heterocysts; wall of gonidium smooth, colorless. 



Massachusetts. Horn Pond, Woburn; South Framingham, November 

 1882. (Farlow). Ludlow Reservoir, Springfield. Fall of 1895. (Jackson and 

 Ellms). Forming a scum on a small pond. Medford. June 1906. (Collins). 



