Myxophyceae 293 



Collins. Preliminary Lists of New England Plants. — V. Marine Algae. Rho- 

 dora. 2: 43. 1900. 



Colonies i mm. to more than a centimeter in diameter, solid, spherical, 

 sometimes coalescing into a cylindrical mass S-8 cm. long, rather firm, deep 

 bluish black when young, later becoming light olive green or pale yellow, 

 not incrusted with lime; filaments 8-20 mic. in diameter, radiating from 

 the center, flexuous in older colonies; sheaths wide, conspicuous, colorless 

 to deep brown in color, very much lamellose and ocreate above; trichomes 

 usually 4 mic. in diameter, occasionally reaching 16 mic, very torulose 

 when young, very little so when older; terminal hairs long and slender in 

 jounger plants, almost wanting in the older ones; cells from one-half to 

 five times as long as broad; transverse walls distinct in younger trichomes, 

 very obscure in older specimens; cell contents provided with a few scat- 

 tered granules, light blue; heterocysts 6-8 mic. in diameter, basal, depressed 

 spherical or ellipsoidal in shape. 



Nova Scotia. (Holden, Setchell). Rhode Island. Forming globular 

 Ihalli on Ruppia maritima in brackish water. Watch Hill Pond, 

 Watch Hill. September 1892. (Setchell). 



533^ Rivularia mexicana (Kuetzing) Rabenhorst. Fl. Eur. Algar. 2: 222. 

 1865. De Toni. Syll. Algar. S: 676. 1907. 



Colonies soft, gelatinous, somewhat spherical or irregular, pale green, 

 at first attached, finally floating free; trichomes 8-10 mic. in diameter, loose- 

 ly entangled, flagelliform, tapering into a golorless hair at the apex. 



Mexico. In stagnant water. (Miiller). 



534. Rivtilaria microscopica Dickie. Notes on the Algae. Sutherland's 



Journal of a Voyage in Baffin's Bay and Barrow Straits in the Years 

 1850-51. 2: 193. 1852. De Toni. Syll. Algar. 5: 677. 1907. 

 Kjellman. Algae of the Arctic Sea. 322. 1883. 



Arctic Regions. Growing on Enteromorpha com press a. 

 American Arctic Sea; Assistance Bay and "other localities." (Dickie). 



535. Zonotrichia minutula Wood. Contr. Hist. Fresh-Water Algae North 



America. 50. 1872. De Toni. Syll. Algar. 5: 675. 1907. 



Colonies very small, somewhat spherical, not distinctly zoned, rather 

 soft, not impregnated with calcium carbonate, blackish green; internal fila- 

 ments very distinctly fasciculately branched; sheaths thick, ample, often 

 pale orange brown, with their apices mostly colorless, torn and open; trich- 

 omes 3-5 mic. in diameter; cells short; heterocysts 6 mic. in diameter, ovate 

 to spherical. 



New York. Forming very small, blackish green, subglobo'se masses, 

 attached to mosses. Clear Pond, Adirondack Mountains. (Wood). 



536. Zonotrichia mollis Wood. Contr. Hist. Fresh-Water Algae North 



America. 48. pi. 4- f- 3- 1872. De Toni. Syll. Algar. 5: 675. ,1907. 

 Colonies somewhat hemispherical, gregarious, often confluent into 

 a mammillose stratum, somewhat soft, grey or flesh-colored, slightly 



