290 Minnesota Algae 



green; filaments crowded; sheaths close, narrow, scarcely distinct, above 

 widened, hyaline or yellowish; trichomes 2.5-5 mic in diameter, ending in 

 a thin hair; lower cells scarcely longer than the diameter, upper cells shorj;- 

 er; cell contents blue-green. 



Greenland. In upper part of littoral zone on sheltered coasts, gregari- 

 ous, but in small numbers. West coast; Baffin Bay, at Tessarmiut, Amera- 

 lik, Pikitsok. (Kjellman). Western part. (Borgesen and Jonsson). Eastern 

 part, south of 70° lat. N. (Rosenvinge). Canada. On rocks and other 

 a^gae. Malpeque, Prince Edward Island. (Faull). New England. Com- 

 mon along the whole coast, on stones, algae and stalks of S p a r t i n a. 

 (Farlow). Maine. Common in upper tide pools. (Collins). Se4 Wall. 

 (Holden). New Hampshire. (Collins). Massachusetts. On shells in 

 harbor; on sides of rock pools, Marblehead, August 1897. (Collins). 

 Rhode Island. (Collins). Connecticut. On turf of S p a r t i n a. Charles 

 Island. September. (Holden). New York. Shores of Long Island. Hell 

 Gate, Flushing Bay. (Pike). New Jersey. Marine. On stones. Atlantic 

 City. (Martindale). California. Common. On stones, algae and other 

 material. (Anderson). ^ I 



Var. confiuens (Kuetzing) Bornet. Les Algues de Schousboe. 29. 1892. 

 De Toni. 1. c. 666. 



Colonies confluent forming a layer or mass. 



Maine. On ground between tide marks. Cape Rosier. July 1897. Con- 

 necticut. On turf of Spartina roots. Charles Island, near Milford. Sep- 

 tember 1896. (Holden). 



529. Rivularia haematites (DC.) Agardh. Syst. Algar. 26. 1824. Bornet and 

 Flahault. Revis. des Nostoc. Ann. Sci. Nat. Bot. VII. 4: 350. 1886. 

 De Toni. Syll. Algar. 5: 668. 1907. 

 Wood. Contr. Hist. Fresh-Water Algae North America. 49. 1872. (Zo- 

 notricha parcezonata Wood). Wolle. Fresh Water Algae. III. 

 Bull. Torr. Bot. Club. 6: 184. 1877. (Zonotrichia haematites 

 Rabenh.). Dickie. On the Algae found during the Arctic Expedition. 

 Journ. Linn. Soc. Bot. 17: 8. 1880. (Zonotrichia fluviatilis Kuetz.). 

 Campbell. Plants of the Detroit River. Bull. Torr. Bot. Club. 13: 93. 1886. 

 (Rivularia calcarea Eng. Bot.). Wolle and Martindale. Algae. 

 Britton's Catalogue of Plants found in New Jersey. Geol. Surv. N. J. 2: 

 603. 1889. (Isactis fluviatilis (Rab.) Kirchn.). Saunders. Pro- 

 tophyta-Phycophyta. Flora of Nebraska. 25. pi. 3. f. 31. 1894. Setchell. 

 Notes on Cyanophyceae. — I. Erythea. 4: 88. 1896. Tilden. American Al- 

 gae. Cent. III. no. 289. 1898; Observations on some West American Thermal 

 Algae. Bot. Gaz. 25: 96. pi. 9. f. 6-9. 1898. 



Plate XX. fig. 11-14. 



Colonies hemispherical, finally confluent and forming a hard, stony 

 crust, up to a centimeter in thickness, green or olive in color, blue-green 

 when dried, zoned in the interior; filaments dense; sheaths close, hyaline 

 or rarely yellowish, fragile, strongly refringent, above ocreate, funnel- 

 shaped, dilated; trichomes 4-7.5 mic. in diameter, ending in a very long 



