Myxophyceae 143 



Algae. Cent. 11. no. 176. 1896; List of Fresh-Water Algae collected in 

 Minnesota during 1896 and 1897. Minn. Bot. Studies. 2: 28. 1898. Saun- 

 ders. The Algae. Harriman Alaska Expedition. Proc. Wash. Acad. Sci. 

 3: 396. 1901. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 20. no. 

 9SS. 1902. Collins. Phycological Notes of the late Isaac Holden. — II. 

 Rhodora. 7: 236. 1905. 



Plate VI. fig. 3. 



Plant mass up to 3 cm. in thickness, expanded, not encrusted with cal- 

 cium carbonate, hard and elastic, composed of layers more or less uniform in 

 color, dull or olive green or reddish; filaments soft, very long, twisted, 

 not or but little branched, separated without rupturing; sheaths cylindrical, 

 firm, contracted or pointed at the apex, at first close and smooth, finally 

 becoming thicker and roughened; trichomes 1.5-2 mic. in diameter, few 

 within the sheath, frequently solitary, somewhat parallel, in living speci- 

 mens not constricted at joints; cells 2-3 mic. in length; transverse walls 

 usually marked by protoplasmic granules; cell contents pale blue-green. 



Alaska. Prince William Sound. June 1899. (Saunders). Forming blood- 

 red gelatinous' patches on smooth, wet, vertical rocks. Cascades, near 

 Iliuliuk. June 1899. (Setchell and Lawson). Forming bright rose-red tufts 

 on rocks exposed to fresh water spray. Near Orca, Prince William Sound. 

 (Setchell). Connecticut. On vertical surface of dripping rock. East 



Rock, New Haven. November. (Holden). Forming rather gelatinous, rusty 

 or dirty green patches on wet vertical faces of trap rock. East Rock, New 

 Haven. December i8gi. (Setchell). Minnesota. In a bottle of distilled 

 water left standing for several months. Botanical Laboratory, University 

 of Minnesota. 1896. (Determined by M. Gomont). 



276. Hypheothrix arenaria (Berkeley). De Toni. Syll. Algar. 5: 342. 1907. 

 Gomont. Monogr. Oscill. 50. pi. 8. f. 11, 12. 1893. (Schizothrix 

 arenaria Gom.). 



Plate VI. fig. 4. 



Plant mass thin, somewhat fragile, not encrusted with calcium car- 

 bonate, blue-green; filaments firm, strongly flexuous, closely entangled, 

 below trunk-shaped, towards the apex divided and branched; false branches 

 strongly twisted and entangled; sheaths firm, roughened in outline, tapering 



at the apex, thick and lamellose in the lower parts; trichomes 1.5-3 mic. in 

 diameter, few in the lower part of the filament, loosely aggregated, some- 

 what parallel, often solitary in the branches, constricted at the joints (in 



dried specimens); apical cell acute-conical; cells up to 5 mic. in length; cell 



contents pale blue-green. 



United States. (Setchell). 



277. Hypheothrix vulpina Kuetzing. Spec. Algar. 267. 1849. De Toni. 

 Syll. Algar. 5: 338. 1907. 



Dickie. On the Algae found during the Arctic Expedition. Journ. Linn. 

 Soc. Bot. 17: 8. 1880. 



Plant mass compact, leathery, opaque, roughened, reddish or dull olive, 



