Minnesota Algae 



a spray of hot water. Valley of Nez Perces Creek, Lower Geyser Basin, 

 Yellowstone National Park. June 1896. (Tilden). 



Further study proved that the Yellowstone specimens should be placed 

 under Hypheothrix calcicola (Ag.) Rab. However, since there is 

 some possibility that the material contains a mixture of the two species, 

 the above description is allowed to stand. 



191. Phormidium crosbyanum Tilden. American Algae. Cent. VII. Fasc. i. 



no. 645. 1909. 



Plate IV. fig. 60, 61. 



Plant mass 2 cm. in thickness, S cm. in diameter, impregnated with lime, 

 firm, somewhat hard, bluish green to brownish red in color; filaments 

 curved, entangled or arranged parallel with each other; sheaths extremely 

 delicate; trichomes 1-2 mic. in diameter, not constricted at joints; apex 

 of trichome straight, neither tapering nor capitate; apical cell conical; 

 calyptra none; cells 1.5-5 niic. long. 



Hawaii. Forming reddish brown, flattened-globose cushions on upper 

 side of rock shelf, between tides. Waianae, Oahu, May 1900. (Tilden). 



It is usually very difficult to make out the sheaths protruding beyond the 

 trichome, but empty sheaths are numerous. 



192. Phormidium treleasei Gomont. Sur quelques Oscillariees nouvelles. 



Bull. Soc. Bot. de France. 46: 2,T. 1899. De Toni. Syll. Algar. 5: 

 234. 1907. 



Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 21. no. 1006. 1903. 

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

 Bot. i: 186. 1903. 



Plant mass expanded, lamellose, composed of many superposed papery 

 layers; filaments parallel, very slender, straight, rigid; sheaths very thin, 

 transparent, mucous, agglutinated; trichomes .6-.8 mic. in diameter, not con- 

 stricted at joints; apex of trichome straight, not tapering; apical cell ro- 

 tund; calyptra none; cells up to 8.8 mic. in length; cell contents pale blue- 

 green. 



Canada. Hot Sulphur Springs, Banff, Alberta. June 1901. (Butler and 

 PoUey). Arkansas. In hot springs. (Trelease). 



193. Phormidium laminosum (Agardh) Gomont. Essai Class. Nostocacees 



homocystees. Morot. Journ. de Bot. 4: 355. 1890; Monogr. Oscill. 

 187. pi. 4. f. 21, 22. 1893. De Toni. Syll. Algar. 5: 225. 1907. 

 WoUe. Fresh Water Algae. III. Bull. Torr. Bot. Club. 6: 183. 1877. 

 (O. elegans Ag.) Tilden. American Algae. Cent. II. no. 181. 1896 

 Observations on some West American Thermal Algae. Bot. Gaz. 25: 98. 

 f. 15. 1898. Bessey, Pound and Clements. Additions to the Reported 

 Flora of the State. Bot. Surv. Nebraska. 5: 13. 1901. Saunders. Thi 

 Algae. Harriman Alaska Expedition. Proc. Wash. Acad. Sci. 3: 398. 1901 

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

 Bot. i: 185. 1903. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc 

 21. no. 1003. 1903. West. West Indian Freshwater Algae. Journ. of Bot 

 42: 292. 1904. Tilden. Notes on a Collection of Algae from Guatemala 



