78 



Collins. New species, etc., issued in the Phycotheca Boreali-Americana, 

 Rhodora. 8: 105. 1906. 



Trichomes 4 mic. in diameter, somewhat flexuous, sometimes coiled 

 in a regular circle, very much constricted at joints; apex of trichome taper- 

 ing, slightly curved, obtuse; calyptra none; cells nearly or quite as long 

 as broad. 



West Indies. Ditches of salt works. Salinas Bay, near Guanica, Porto 

 Rico. June 1903. (Howe). 



154. Oscillatoria laetevirens Crouan. Liste des Algues marine decouvertes 



dans le Finistere, etc. Bull. Soc. Bot. France. 7: 371. i860. Gomont. 



Monogr. Oscill. 246. pi. 7. f. 11. 1893. De Toni. Syll. Algar. 5: 177. 



1907. 

 Collins. Preliminary Lists of New England Plants. V. Marine Algae. 

 Rhodora. 2: 42. 1900. Tilden. Collection of Algae from the Hawaiian 

 Islands. Hawaiian Almanac and Annual for 1902. 113. igoi; American Algae. 

 Cent. V. no. 496. 1901. Collins, Holden and Setchell. Phyc. Bor.-Am. 

 Fasc. 22. no. 1054. 1903. Setchell and Gardner. Algae of Northwestern 

 Ainerica. Univ. Calif. Pub. Bot. i: 184. 1903. West. West Indian Fresh- 

 water Algae. Journ. of Bot. 42: 292. 1904. Collins. Phycological Notes of 

 the late Isaac Holden. — I. Rhodora. 7: 172. 1905. Lemmermann. Algenfl. 

 Sandwich-Inseln. Bot. Jahrb. 34: 618. 190S. 



Plate IV. fig. 28. 



Plant mass thin, membranaceous, bright blue-green; trichomes 3-5 mic. 

 in diameter, straight, fragile, slightly constricted at the joints; apex of 

 trichome briefly tapering, undulating and hooked, rarely straight; apical 

 cell more or less obtuse or somewhat pointed, not capitate; calyptra none; 

 cells 2.5-5 mic. in length; transverse walls granulated or cell contents uni- 

 formly granular, yellowish green. 



Maine. On woodwork under old tide mill. Harpswell. July 1903. (Col- 

 lins). Rhode Island. (Collins). Connecticut. Forming a film on old 

 grassy bottom, brackish marsh pool. Cook's Point. June. (Holden). Wash- 

 ington. In salt marsh. Head of Penn's Cove, Whidbey Island. (Gardner). 

 West Indies. On roots of mangroves in brackish swamp. Near Bridgetown; 

 Graeme Hall Swamp, Barbados. (Howard). Hawaii. Forming a delicate, 

 bright blue-green stratum covering bottom of tide pool in rocks into which 

 water splashes at high tide. Waianae, Oahu. May 1900. (Tilden). Washings 

 from marine algae. (Schauinsland). 



155. Oscillatoria acuminata Gomont. Monogr. Oscill. 247. pi. 7. f. 12. 1893. 



De Toni. Syll. Algar. 5: 177. 1907. 

 Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 27. no. 1303. 1906. 

 Plate IV. fig. 29. 



Plant mass blue-green; trichomes 3-5 mic. in diameter, straight, fragile, 

 sometimes slightly constricted at joints; apex of trichome briefly tapering, 

 very sharply pointed, hooked or twisted, not capitate; apical cell mucronate; 

 calyptra none; cells 5.5-8 mic. in length; transverse walls granulated or en- 

 tire cell contents filled with granules. 



