170 Minnesota Algae 



Plate VII. fig. 12-14. 



Plant mass gelatinous-membranaceous, irregularly expanded, adhering 

 by under surface, tuberculose, dull olive or dark-colored; filaments flex- 

 uous, densely entangled; trichomes 3-4 mic. in diameter, similar, olive; 

 cells spherical or barrel-shaped, or cylindrical, about twice as long as broad; 

 heterocysts somewhat globose, 6-7 mic. in diameter; gonidia 4-8 mic. in 

 diameter, 8-12 mic. in length, oblong, in a catenate series, numerous; wall 

 of gonidium smooth, yellowish. 



Arctic Regions. Fresh water. Port Kennedy. (Lat. 72° N.) (Walker). 

 Alaska. Near Iliuliuk, Unalaska. July 1899; forming soft gelatinous lumps 

 and masses of various shapes, on rocks among mosses, Amaknak Cave, 

 Amaknak Island, Bay of Unalaska. (Setchell and Lawson). Canada. 

 Cumberland Sound, Davis Strait. (Taylor). In brown bunches on sides 

 of rock among moss. Just above high tide. Baird Point. Minnesota Sea- 

 side Station, Vancouver Island, British Columbia. August 1898. (Tilden). 

 Newfoundland. Signal Hill, St. Johns. July 1897. (Holden). Maine. On 

 sand by roadside, near seashore, in company with Microcoleus vagi- 

 natus Harpswell. July 1904. (Collins). New Hampshire. On mosses. 

 Berlin Falls, near Shelburne. 1882, 1883. (Farlow). Massachusetts. 



Maiden swamp in Middlesex Fells, Newton. (Farlow). Minnesota. On 

 moist ground, among mosses and liverworts. St. Louis Park, Minneapolis. 

 October 1901. (Hone). Iowa. On the stems of mosses. Fayette. 1905. 



(Fink). Nebraska. On wet rocks and on the moss covering them. 

 (Saunders). Montana. Abundant on moss under dripping rocks. (Ander- 

 son and Kelsey). Washington. Moist ground just above high watei 

 mark. Whidbey Island. (Gardner). West Indies. Growing on sides ot 

 road. Fort Charlotte, St. Vincent Island. 



321. Nostoc humifusum Carmichael sec. Harvey in Hooker's British Flora. 



2: 399. 1833. Bornet and Flahault. Revis. des Nostoc. Ann. Sci. 



Nat. Bot. VII. 7: 201. 1888. De Toni. Syll. Algar. 5: 402. 1907. 

 WoUe. Fresh-Water Algae U. S. 280, 282. 1887. West and West. 

 On some Freshwater Algae from the West Indies. Journ. Linn. Soc. Bot. 

 30: 269. 189s; A Further Contribution to the Freshwater Algae of the 

 West Indies. Journ. Linn. Soc. Bot. 34: 288. 1898-1900. 



Plate VII. fig. IS. 



Plant mass gelatinous or mucous, irregular, of various sizes, some- 

 times punctiform, sometimes widely expanded from the confluence of many 

 colonies, tuberculate, olive or brownish in color, adherent on under sur- 

 face; filaments twisted and flexuous, densely entangled; sheaths usually 

 yellowish and distinct throughout the mass, sometimes not distinct; trich- 

 omes 2.2-3 mic. in diameter; cells somewhat globose or twice as long as 

 the diameter; heterocysts 3 mic. in diameter, somewhat spherical; gonidia 

 4 mic. in diameter, 6 mic. in length, somewhat globose or oval, with smooth 

 and yellowish outer membrane; cell contents blue-green. 



Florida. Colonies "inflated even to the size of a man's head." Island 

 of Anastatia. (Smith). West Indies. On lime-trees. Shanford Estate; 

 on trees, summit of Trois Pitons (4500 feet), November and December 



