Myxophyceae " 235 



Plate XIV. fig. 9. 



Plant mass expanded, variously tinged with red, purple and black; 

 filaments 12-15 mic. in diameter, loosely interwoven, much branched; 

 sheaths wide, yellowish, or colorless; cells as long or twice as long as 

 their diameter; heterocysts spherical or oblong, two or three in series; cell 

 contents granular, dull blue-green. 



Pennsylvania. On dripping, gelatinous, exposed rocks. Delaware Water 

 Gap. July. (Wolle). 



435. Tolypothrix glacialis Dickie. On the Algae found during the Arctic 



Expedition. Journ. Linn. Soc. Bot. 17: 8. 1880. De Toni. Syll. Al- 

 gar. 5: 556. 1907. 



Plant mass caespitose, brown; filaments 15 mic. in diameter, rigid; 

 sheaths somewhat lamellose; transverse walls indistinct. 



Arctic Regions. Forming a brownish crust on decayed N o s t o c. Edge 

 of Glacier Lake, Cape Baird. (300 feet), 81° 30' N. (Dickie). 



Genus DESMONEMA Berkeley and Thwaites. 

 English Botany. 1849. 



Plant mass caespitose, penicillate; filaments somewhat dichtomously 

 divided, straight; sheaths thin; trichomes two or more within the sheath; 

 heterocysts basal; gonidia large, oval or elliptical, single or in short series; 

 wall of gonidium somewhat thick. 



436. Desmonema wrangelii (Agardh) Bornet and Flahault. Revis. des 



Nostoc. Ann. Sci. Nat. Bot. VIL 5: 127. 1887. De Toni. Syll. 

 Algar. s: 558. 1907. 



Wolle. Fresh- Water Algae U. S. 237. pi. 168. f. 3, 4. 1887. (C a 1 o t h r i x 

 d i 1 1 w y n i i Hass.) Wolle and Martindale. Algae. Britton's Catalogue 

 of Plants found in New Jersey. Geol. Surv. N. J. 2: 603. 1889. (Also C. 

 radios a (Kg.) Kirchn.). Setchell. Notes on some Cyanophyceae of 

 New England. Bull. Torr. Bot. Club. 22: 428. 1895. Collins, Holden and 

 Setchell. Phyc. Bor.-Am. Fasc. 3. no. 108. 1895. Saunders. The Algae. 

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

 ell and Gardner. Algae of Northwestern America. Univ. Calif. Pub. Bot. 

 i: 196. 1903. 



Plate XIV. fig. 10. 



Plant mass 5-6 mm. in height, caespitose, formed of penicillate fascicles, 

 gelatinous, dark green; filaments erect, somewhat flexuous, repeatedly sub- 

 dichotomously branched; sheaths thin, continuous, colorless or yellowish; 

 trichomes 9-10 mic. in diameter, constricted at the joints; cells three times 

 shorter than the diameter; heterocysts one, two or none; cell contents 

 tlue-green. 



Alaska. In a clear brook, emptying into Glacier Bay; in brook, Popof 

 Island. (Saunders). On stones in brooks or lakes, or even in pools on the 

 tundra. St. Michael. (Setchell). Near Iliuliuk, Unalaska. (Setchell and 

 Lawson). Connecticut. Very abundant. Forming small tufts or extended 



