Myxophyceae 285 



Nebraska. On water plants. Minden. (Saunders). Montana. On leaflets 

 of Myriophyllum. Common in Sand Coulee Creek. (Anderson and 

 Kelsey). 



519. Rivularia natans (Hedwig) Welwitsch. Synopsis Nostochinearum 



Austriae Inferioris. 17. 1836. Bornet and Flahault. Revis. des Nos- 

 toc. Ann. Sci. Nat. Bot. VII. 4: 369. 1886. De Toni. Syll. Algar. 

 5: 648. 1907. 



Wood. Contr. Hist. Fresh-Water Algae North America. 47. 1872. (G 1 o e- 

 otrichia angulosa Rab.). WoUe. Fresh Water Algae. II. Bull. 

 Torr. Bot. Club. 6: 138. 1877; Fresh-Water Algae U. S. 246. pi. 178. f. 4-20; 

 pi. 179. f. 10, II. 1887. Rabenhorst. Algen Europa's. no. 2539. (Gloio- 

 trichia parvula Rabenh.). Bennett. Plants of Rhode Island. 114. 

 1888. Wolle and Martindale. Algae. Britton's Catalogue of Plants found 

 in New Jersey. Geol. Surv. N. J. 2: 604. 1889. Saunders. Protophyta-Phy- 

 cophyta. Flora of Nebraska. 24. pi. 3. f. 32. 1894. Tilden. American Algae. 

 Cent. I. no. 80. 1894; List of Fresh-Water Algae collected in Minnesota dur- 

 ing 1894. Minn. Bot. Studies, i: 236. 1895. Collins, Holden and Setchell. 

 Phyc. Bor.-Am. Fasc. 5. no. 214. 1896. Collins. The Algae of Jamaica. 

 Proc. Am. Acad. 37: 242. 1901. Tilden. American Algae. Cent. VI. no. 569. 

 1902. Kellerman. Proposed Algological Survey of Ohio. Ohio Nat. 2: 222. 

 1902. Clark. The Holophytic Plankton of Lakes Atitlan and Amatitlan. 

 Guatemala. Proc. Biol. Soc. Wash. 21: 98. 1908. 



Plate XIX. fig. 7, Plate XX. fig. 1-3. 



Colonies up to 10 cm. in diameter, spherical, bullate, hollow, soft, dull 

 olive green; filaments loosely associated; trichomes 7-9 mic. in diameter, 

 tapering into a thick hair; lower cells barrel-shaped, about as long as 

 wide, upper cells shorter than the diameter; cell contents olive; hetero- 

 cysts 6-12 mic. in diameter, usually spherical; gonidia without sheath 

 10-18 mic. in diameter, 40-250 mic. in length; external sheaths up to 40 mic. 

 in diameter, often wide, folded and wrinkled, transparent or brownish, with 

 smooth surface. 



Rhode Island. (Bailey). New York. Attached to water plants, in 

 pools. Buffalo. (Wolle). When young attached to stones and weeds, after- 

 v/ards floating free. Shore of Cayuga Lake, Ithaca. September 1895. (Atkin- 

 son). New Jersey. In small ponds and pools. (Wolle). Pennsylvania. 

 On water plants. Bethlehem. July 1877. (Wolle). Ohio. (Kellerman). 

 Minnesota. Floating near edge of artificial lake Minneapolis. August 1894; 

 on pondweeds in pond. Woodland Park, Duluth. August 1901. (Tilden). 

 Nebraska. Minden. (Saunders). Central America. Among sponges. (Meek). 

 West Indies. Under Nymphaea leaves. Botanic Garden, Castleton, Ja- 

 maica. April 1893. (Humphrey). Hawaii. Forming soft brown velvety 

 masses, appearing spherical in the water, collapsing when taken out. In 

 lower terrace water of rice field, with Chara. Aiea, Oahu. June 1900. (Til- 

 den). 



520. Rivularia incrustata (Wood) De Toni. Syll. Algar. 5: 656. 1907. Wood. 



Contr. Hist. Fresh-Water Algae North America. 45. pi. 3. f. 4. 

 1872. (Gloeotrichia incrustata Wood). 



