Myxophyceae 263 



Plant mass crustaceous, flattened; filaments 8-12 mic. in diameter, more 

 slender than in the typical form. 



Massachusetts. On rocks in littoral zone. Revere Beach. September 



:89s. (Collins). 



473. Calothrix vivipara Harvey. Nereis Boreali-Americana. Part III. 106. 



1858. Hornet and Flahault. Revis. des Nostoc. Ann. Sci. Nat. Bot. 

 VII. 3: 362. 1886. De Toni. Syll. Algar. 5: 616. 1907. 

 Farlow. List Marine Algae U. S. Proc. Am. Acad. Arts Sci. 10: 380. 

 1875; Marine Algae of New England. 37. 1881. Wittrock and Nordstedt. 

 Algae Aq. Dulc. Exsicc. no. 1307. 1896. Collins, Holden and Setchell. 

 Phyc. Bor.-Am. Ease. 12. no. 560. 1899. Collins. Preliminary Lists of New 

 England Plants. — V. Marine Algae. Rhodora. 2 : 41. 1900. 



Plant mass widely expanded, velvety, blackish green; filaments 12-24 

 mic. in diameter, 3-5 mm. in length, decumbent and interwoven at the 

 base, becoming erect, somewhat flexuous, branched; false branches in pairs, 

 issuing from the filament as in Scytonema; sheaths thick, gelatinous, uni- 

 form, yellowish brown, somewhat opaque; irichomes 9-15 mic. in diame- 

 ter, tapering very gradually from base to apex, ending in a hair; cells equal 

 to or shorter than their diameter; heterocysts basal and a few scattered 

 through the trichome; cell contents olive green. 



Massachusetts. Forming patches on rocks and growing also on other 

 algae. Nahant; Wood's HoU. (Farlow). In upper tide pools on smooth 

 rocks. Marblehead. August 1895. (Collins). Rhode Island. (Bailey). Sea- 

 connet Point. (Farlow). 



474. Calothrix pilosa Harvey. Nereis Boreali-Americana. Part III. 106. pi. 



48 C. 1858. Bornet and Flahault. Revis. des Nostoc. Ann. Sci. Nat. 

 Bot. VII. 3: 363. 1886. De Toni. Syll. Algar. 5: 614. 1907. 



Murray. Catalogue of the Marine Algae of the West Indian Region. 

 Journ. of Bot. 27: 261. 1889. (Scytonema submarinum Crn.). Col- 

 lins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 18. no. 859. 1901. Collins. 

 The Algae of Jamaica. Proc. Am. Acad. 37: 242. 1901. Collins, Holden 

 and Setchell. Phyc. Bor.-Am. Fasc. 24. no. 1167. 1904. 



Plant mass caespitose, widely expanded, black or dark blue-green; 

 filaments 10-40 mic. in diameter, 2-10 mm. in length, decumbent and inter- 

 woven at the base, erect at the apices, elongate, rigid, free or growing to- 

 gether laterally in fascicles, distinctly thicker in upper portions; sheaths 

 hard, thick, at first orange, finally yellowish brown, opaque, uniform; trich- 

 omas 10-20 mic. in diameter, briefly tapering at the apex; terminating in a 

 hemispherical cell, here and there interrupted by heterocysts; cell contents 

 olive brown. 



Florida. Forming blackish or dark brown, pilose strata of indefinite ex- 

 tent. On rocks between tide marks. Key West. (Harvey). California. 

 Forming a black velvety covering on the bottoms of small pools in the 

 rocks above high water mark, but filled with salt water from the spray and 

 higher waves, though often much concentrated by the sun. Near Point 

 Carmel, Monterey County. June 1901. (Setchell). West Indies. Guade- 

 loupe. (Maze). On Bostrychia tenella. Port Antonio, Jamaica. 



