74 Minnesota Algae 



Buchansui. Notes on the Algae of Iowa. Proc. Iowa Acad. Sci. 14: 

 14. 1908. Tilden. American Algae. Cent. VII. Fasc. i. no. 646. 1909. 



Plate IV. fig. 19, 20. 



Plant mass thin, of a beautiful blue-green color; trichomes 2-3 mic. 

 in diameter, straight or curved, fragile, not constricted at joints, curved 

 gradually at the end; apex of trichome neither tapering nor capitate; apical 

 cell rotund above; calyptra none; cells 4-8.5 mic. in length; transverse walls 

 commonly marked by two protoplasmic granules; cell contents pale blue- 

 green. 



Greenland. Western part at 60° N. lat. (Rosenvinge). Eastern and 

 western parts. (Borgesen and Jonsson). United States. Coating wood 

 subject to hot waste water from steam engines." Temperature about 110° 

 F. (WoUe). Maine. In fresh water. (Holden). Massachusetts. On 

 rocks and trunk of trees. (Collins). Connecticut. On muddy bottom of 

 Bruce's Brook, Bridgeport. (Holden). Texas. 1902. (Fanning). Ohio. 

 Plankton. Put-in-Bay, Lake Erie. (Snow). Minnesota. In pool. Oatka 

 Beach, Minnesota Point, Duluth. August 1901. (Tilden). Iowa. In stag- 

 nant water and on soil. Fayette. (Fink). Effluent of the filter beds of the 

 college sewage disposal plant; on the soil in greenhouse, Ames; pond. 

 Eagle Grove. (Buchanan). South Dakota. Floating in large dark blue- 

 green masses on surface of water. Lake Hendricks. August 1898. (Allen 

 and Saunders). Nebraska. In Salt Creek; in cultures. Lincoln. (Bessey). 

 In ditches and ponds among other algae. (Saunders). Wyoming. Lining 

 channel of spring. Above Beehive Geyser, Upper Geyser Basin, Yellow- 

 stone National Park. 1897. (Weed). Washington. In mud at bottom of 

 ponds. Whidbey Island. (Gardner). 



145. Oscillatoria subtilissima Kuetzing. Tab. Phyc. i : 27. pi. 38. f. 7. 1845-49. 



De Toni. Syll. Algar. 5: 171. 1907. 



Bennett. Plants of Rhode Island. 115. 1888. Snow. The Plankton 

 Algae of Lake Erie. U. S. Fish Comm. Bull, for 1902. 22: 392. 1903. 



Trichomes 1-1.5 mic. in diameter, solitary or scattered, rarely asso- 

 ciated in a yellowish-green mass, slender, straight or rolled in a circinate 

 manner; cell walls inconspicuous; cell conents homogeneous, yellowish- 

 green. 



Rhode Island. Common. (Bennett). Ohio. Plankton. Put-in-Bay, 

 Lake Erie. (Snow). 



146. Oscillatoria geminata Meneghini. Conspectus Algologiae euganeae. 9. 



1837. Gomont. Monogr. Oscill. 242. pi. 7. f. 6. 1893. De Toni. Syll. 

 Algar. 5: 172. 1907. 



Tilden. American Algae. Cent. II. no. 191. 1896; List of Fresh-water 

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

 2: 28. 1898; Observations on some West American Thermal Algae. Bot. 

 Gaz. 25: 102. pi. 9. f. 22. 1898; American Algae. Cent. VI. no. 595. 1902. 

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

 Bot. i: 183. 1903. 



Plant mass dull yellowish-green; trichomes 2.3-4 mic. in diameter, 



