294 Minnesota Algae 



zoned; filaments up to 4.2 mic. in diameter, very long, narrow, flexuous; 

 sheaths close, colorless, firm, not fibrous; trichomas up to 2 mic. in diame- 

 ter, often interrupted; transverse walls visible; cells equal to up to four 

 times longer than broad; heterocysts single, spherical. 



New York. On dripping rocks. Cave of the Winds, Niagara. (Wood). 



Genus BRACHYTRICHIA Zanardini. 

 Phyc. Indie. Pugillus. 24. 1872. 



Colonies at first solid, finally becoming hollow, made up of Nostoc- 

 like filaments embedded in gelatin; filaments flexuously curved, parallel, 

 above tapering and drawn out into a hair at the apex, very much branched; 

 sheaths distinct in the young filaments, tubular, finally becoming confluent 

 and invisible; heterocysts intercalary, arranged without any order. 



537. Brachytrichia quoyi (Agardh) Hornet and Flahault. Revis. des Nos- 

 toc. Ann. Sci. Nat. Bot. VII. 4: 373. 1886. De Torii. Syll. Algar. 

 5: 680. 1907. 



Farlow. List of the Marine Algae of the United States, is. 1876. (Ri vu- 

 laria nitida?). Bornet in Farlow, Anderson and Eaton. Algae Am. 

 Bor. Exsicc. no. 45. 1876. (Hormactis farlowii Born.) ; in Farlow. 

 Marine Algae of New England. 39. pi. 2. f. I. 1881. (Hormactis quoyi 

 (Ag.) Bornet). Pike. Check List of Marine Algae. Bull. Torr. Bot. Club. 

 13: 106. 1886. Martindale. Marine Algae of the New Jersey Coast and 

 Adjacent Waters of Staten Island. Mem. Torr. Bot. Club, i : 91. 1889. 

 Wolle and Martindale. Algae. Britton's Catalogue of Plants found in New 

 Jersey. Geol. Surv. N. J. 2: 604. 1889. Hauck and Richter. Phyk. Univ. 

 no. 681. 1890. Schiveley. Hormactis quoyii. Proc. Phil. Acad. 1890: 497. 

 1891. Wittrock and Nordstedt. Algae Aq. Dulc. Exsicc. no. 1197. 1893. 

 Collins, Holden and Setchell. Phyc. Bor.-Am. Ease. i. no. 8. 1895. Col- 

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

 dora. 2: 41. 1900. 



Plate XX. fig. 18. 



Colonies up to 5 cm. in diameter, plicate-expanded and buUate, conflu- 

 ent, blackish green. 



Massachusetts. Growing on F u c u s at half tide. Wood's Holl. (Far- 

 low). Falmouth; Wood's Holl. July 1892. (Collins). Forming bladders 

 on stems of old Fucus vesiculosus L. Quamquisset Harbor, Fal- 

 mouth. August 1890. (Setchell). New York. Shores of Long Island. 

 Greenport. July. (Pike). New Jersey. Atlantic City. (Morse). Cal- 

 ifornia. Pacific Ocean. (Grunow). 



Families and Genera not well understood. 



Genus ASTEROTHRIX Kuetzing. Phyc. Gen. 20Q. 1843. 



Filaments very rigid, nude, with cuspidate, obtuse or acute ends, some- 

 what genuflexuous, branched at right angles; transverse walls usually in- 

 distinct; propagation unknown. 



