Myxophyceae 167 



Plate VII. fig. 2. 



Colonies at first globose, light blue-green, afterwards becoming bullose 

 and variously tuberculate, mucous or gelatinous, dark blue-green; filaments 

 flexuous, moderately entangled; sheaths distinct near the surface of the 

 mass, dark-colored, those in the interior confluent, transparent; trichomes 

 4 mic. in diameter, pale olive green; cells depressed spherical or about 

 twice as long as the diameter; heterocysts 4-5.6 mic. in diameter, some- 

 what spherical or oblong; gonidia 6-7 mic. in diameter, globose, in a long- 

 catenate series, approximate, with a smooth, transparent outer layer grown 

 together with the sheath. 



Greenland. Karajak. (Richter). Canada. Pool near Bow River, Lag- 

 gan. Alberta. July 1901. (Butler and PoUey). California. In stagnant 

 pool. Near Pasadena. May 1896. (McClatchie). Hawaii. In ditches and 

 pools between Honolulu and Waikiki, Oahu. 1896-97. (Schauinsland). 



316. Nostoc rivulare Kuetzing. Tab. Phyc. 2: 3. pi. 10. f. 3. 1850. Bornet 



and Flahault. Revis. des Nostoc. Ann. Sci. Nat. Bot. VII. 7: 195. 

 1888. De Toni. Syll. Algar. 5: 395. 1907. 



Setchell and Gardner. Algae of Northwestern America. Univ. Calif. 

 Pub. Bot. i: 189. 1903. 



Colonies at first globose, of various sizes, soon becoming bullate, 

 tuberculate, hollow, then irregularly torn and perforated, lobed, fragile, at 

 first light green, when older becoming yellowish or of various colors; 

 filaments loosely entangled, moderately flexuous; sheaths distinct, yellow- 

 ish at the surface of the mass, those in the interior transparent and con- 

 fluent; trichomes 4-4.2 mic. in diameter; cells spherical oblong, a little 

 longer than the diameter; heterocysts 5-6 mic. in diameter, oblong; go- 

 nidia 6-8 mic. in diameter, 7-10 mic. in length, oblong or barrel-shaped, 

 contiguous when mature, with smooth, transparent or dark-colored outer 

 membrane. 



Alaska. Forming floating masses of light brown jelly in springs and 

 pools. Near Huntville, Unalaska. (Setchell and Lawson). Washington. 

 Near Green Lake, Seattle. (Gardner). 



317. Nostoc carneum Agardh. Syst. Algar. 22. 1824. Bornet and Flahault. 



Revis. des Nostoc. Ann. Sci. Bot. VII. 7: 196. 1888. De Toni. 

 Syll. Algar. s : 395- I907- 

 Setchell and Gardner. Algae of Northwestern America. Univ. Calif. 

 Pub. Bot. i: 190. 1903. Collins, Holden and Setchell. Phyc. Bor.-Am. 

 Fasc. 29. no. 1403- I907- 



Plate VII. fig. 3- 



Colonies globose when young, later bullose, tuberculate, hollow, after- 

 wards becoming irregular in form, expanded, diffluent into a gelatinous 

 mucus, flesh-colored, dark-colored or pale blue-green; filaments loosely 

 entangled, moderately flexuous; sheaths indistinct, transparent; trichomes 

 <(.S-4 mic. in diameter; cells oblong cylindrical, about twice as long as wide; 

 heterocysts 6 mic. in diameter, oblong; gonidia 6 mic. in diameter, 8-10 



