8o Minnesota Algae 



there interrupted by inflated, refringent cells; apex of trichoma somewhat 

 pointed, briefly tapering, hooked or twisted, not capitate; calyptra none; 

 cells 1.5-2.8 mic. in diameter; transverse walls not granulated; cell contents 

 finely granular. 



New York. Forming an extended stratum on a shaded deposit of mud 

 after an inundation. Buffalo. (Wolle). New Jersey. Fresh water, in 



marshes, frequent. (Wolle). Minnesota. Growing on clods of damp earth 

 in greenhouse. St. Paul. November 1894; in pool coating bottom, submerged 

 leaves and sticks, Lincoln Park, Duluth. (Tilden). California. Pool by 

 roadside. North Berkeley. February 1903. (Gardner). West Indies. 



(Kunze). Near Bridgetown; Bay Estate, Barbados. (Howard). 



Var. neapolitana (Kuetz.) Gomont. 1. c. 249. De Ton:. 1. c. 181. 



Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 27. no. 1304. 1906. 



Trichomes 5-6.5 mic. in diameter; apex of trichome hooked or twisted. 



California. In pool in salt marsh. Oakland, July 1905. (Gardner). 



159. Oscillatoria cruenta Grunow in Rabenhorst. Fl. Eur. Algar. 2: 100. 



1865. De Toni. Syll. Algar. 5: 182. 1907. 



Wolle. Fresh-Water Algae U. S. 312. pi. 206. f. s; pi. 207. f. 1-3. 1887. 

 Clark. The Holophytic Plankton of Lakes Atitlan and Amatitlan, Guate- 

 mala. Proc. Biol. Soc. Wash. 21: 96. 1908. 



Plant mass mucous, dark purple; trichomes 4-7 mic. in diameter; apical 

 cell obtuse, straight, rarely slightly curved; cells 2-4 mic. in length; trans- 

 verse walls granulated; cell contents pale brown or blue-green. 



Pennsylvania. Imbedded in large submerged hyaline or greenish or 

 purplish, firm gelatinous masses of irregular form, averaging about the size 

 of a man's head. In mountain spring at about 1500 feet elevation. (Wolle). 

 Central America. Abundant, forming a flat, gelatinous, striated stratum, 

 brownish in color, about 4 mm. thick, obtained from the surface between 

 pools of hot water. Laguna. January 1906. (Meek). 



160. Oscillatoria formosa Bory. Diet. Class. d'Hist. Nat. 12: 474. 1827. 



Gomont. Monogr. Oscill. 250. 1893. De Toni. Syll. Algar. 5: 182. 

 1907. 

 Maze and Schramm. Essai Class. Algues Guadeloupe. 16. 1870-1877. (O. 

 thermalis). Tilden. American Algae. Cent. II. no. 192. 1896. Col- 



lins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 15. no. 710. 1900. Bessey, 

 Pound and Clements. Additions to the Reported Flora of the State. Bot. 

 Surv. Nebraska. 5: 13. 1901. Collins. The Algae of Jamaica. Proc. Am. 

 Acad. Arts Sci. 37: 239. 1901. Tilden. Algae collecting in the Hawaiian 

 Islands. Postelsia: The Year Book of the Minnesota Seaside Station, i: 166. 

 1902. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 22. no. 1053. 

 1503. Collins. Phycological Notes of the late Isaac Holden. — I. Rhodora. 

 7: 172. 1905. 



Plate IV. fig. 33. 



Plant mass dark blue-green; trichomes 4-6 mic. in diameter, straight, 

 elongate, flexuous, usually slightly constricted at joints; apex of trichome 

 somewhat obtuse and briefly tapering or rotund, hooked, not capitate; calyp- 



