MARINE ALGM OF BEAUFORT, N. C. 413 



3. Lyngbya lutea (Agardh) Gomont, ex Gomont. 



Oscittatoria lutea, Agardh, 1824, p. 68. 



Lyngbya tenerrima, Farlow, 1882, p. 35. 



Lyngbya jvliana, Wolle, 1887, p. 301, pi. 202, f. 20-31. 



Lyngbya lutea, Gomont, 1890, p. 354. 



Lyngbya lutea, Gomont, 1892, tome 16, p. 141, pi. 3, f. 12-13. 



Lyngbya lutea, Forti, in De Toni, 1907, p. 275. 



Lyngbya lutea, Tilden, 1910, p. 114, pi. 5, f. 30-31. 



P. B.-A. No. 854. 



Plant mass somewhat gelatinous, leathery, yellowish brown, or olive, often becoming dark violet 

 when dry; filaments coiled, flexible, densely entangled; sheaths colorless, smooth, at first thin, later 

 becoming thick (up to 3 mic.) and lamellose ; trichomes not constricted at the joints, not tapering at the 

 apices, 2.5 to 6 mic. in diameter, cells 1.5 to 5.5 mic. long, apical cell showing a rotund calyptra, trans- 

 verse walls usually not distinct, cell contents granular, olive green. 



Maine to Florida and Alabama; West Indies; Europe; Dalmatia; northern Africa. 



In sparse tufts on marine grasses, shoals west of laboratory, Beaufort, N. C., August, 1907. 



Genus 5. Hydrocoleum Kuetzing, ex Gomont. 



Hydrocoleum, Kuetzing, 1843, p. 196. 

 Hydrocoleum, Gomont, 1892, tome 15, p. 332. 

 Hydrocoleus, Forti, in De Toni, 1907, p. 315. 

 Hydrocoleus, Tilden, 1910, p. 134. 



Filaments possessing evident sheaths, forming heaped or indefinite masses, or layers 

 not massed, giving a tangled mat, very rarely hardened with lime; sheaths always color- 

 less, cylindrical, somewhat lamellose, more or less mucous or somewhat formless and 

 entirely dissolving on the older filaments; trichomes few within the sheath, often loosely 

 aggregated, more or less false branching, apex of trichome straight, more or less attenu- 

 ated, outer membrane of apical cell thickened into a calyptra, cells shorter than the 

 diameter of the trichome, in some species very short. 



Twenty species in fresh and salt water throughout the world, mostly marine. 

 Hydrocoleum lyngbyaceum Kuetzing, ex Gomont. 



Hydrocoleum lyngbyaceum, Kuetzing, 1849, p. 259. 



Lyngbya arenarium, Wolle, 1887, p. 299, pi. 201, f. 27-29. t 



Hydrocoleum lyngbyaceum, Gomont, 1892, tome 15, p. 337, pi. 12, f. 8-10. 



Hydrocoleus lyngbyaceus, Forti, in De Toni, 1907, p. 31?- 



Hydrocoleus lyngbyaceus, Tilden, 1910, p. 135, pi. 5, f . 58. 



P. B.-A.- Nos. 204, 205. 



Dark green mats or a broadly expanded gelatinous layer; filaments adnate, unbranched at base, 

 branched in upper portions, false branches numerous, somewhat appressed; sheaths wide, mucous, 

 containing one or more trichomes, roughened in outline, acuminate or often open at apex, sometimes 

 entirely dissolved and agglutinated; trichomes 8 to 16 mic. in diameter, not constricted at the joints, 

 numerous at the base of the filaments, spirally twisted and entangled, solitary in the branches, cells 

 2.5 to 4.5 mic. long, apex of trichome attenuated, truncate, transverse walls granulated. 



Massachusetts to Florida; Bermuda; West Indies; warm and temperate waters generally. 



Fairly abundant on Gelidium caerulescens , Duncan breakwater, Beaufort, N. C., forming small 

 tufts i to 2 cm. long tangled in the upper branches of the host. 



Genus 6. Microcoleus Desmazieres, ex Gomont. 



Microcoleus, Desmazieres, 1823, p. 7. 

 Microcoleus, Gomont, 1892, tome 15, p. 350. 



Filaments possessing evident sheaths, simple or vaguely branched; sheaths colorless, 

 more or less regularly cylindrical, not lamellose, in some species finally dissolving; 

 trichomes many within a sheath, closely crowded, often twisted into ropelike bundles in 

 well- developed filaments, apex of trichome straight, attenuated, apical cell acute, 

 rarely obtusely conical, capitate in one species. 



