82 COLLINS AND HEHVEY. 



branches, elongate, \irgate, bearing leaves, fructification, and short 

 branches; stems slender, terete, densely mirriculate with short simple 

 or forked papillae, which are occasionally more scattered on the older 

 parts; leaves thickly set at the tips of the main branches and along 

 short lateral branches, linear and attenuate to both ends, 1-2 mm. 

 wide, up to 5 cm. long, simple or forked, margin irregularly dentate with 

 small distant teeth, in young leaves larger and more frequent; midrib 

 not specially conspicuous; cryptostomata rather large, a single series 

 each side of the midrib, rather irregularly spaced; vesicles 3-6 mm. 

 diam., smooth, or sometimes with cryptostomata, subspherical on a 

 filiform pedicel of uniform diameter, or pjrriform on a pedicel enlarged 

 above; pedicel smooth, length one and one half to three times the 

 diameter of the vesicle, usually unarmed, occasionally with a small 

 mucro, rarely with a short filiform prolongation. Rachis of fructifica- 

 tion usually short, sterile and filiform, or fertile and torulose, bearing 

 several alternate, torulose, fertile branches, with subacute tip, one 

 half to one cm. long; fructification mostly on the lower part of short 

 branches of the second order with leaves about them on the branches. 



The above description refers to the attached plant of quiet waters, 

 but indi^-iduaJs more slender than the typical form can be found, in 

 which the stem is almost entirely smooth and the rachis of fructifica- 

 tion quite elongate. As with other species of Sargassum, individuals 

 are to be found among the masses of S. natans floating after storms, 

 and these show a certain resemblance to the latter, but their condition 

 shows indications of their not persisting. 



4. S. LEXDiGERUM (L.) Agardh, 1820, p. 9; P. B.-A., No. 2178; 

 Fucus lendigerm Linnaeus, 1763, p. 1628; Turner, 1808, p. 107, PL 

 XLYIII. South shore, various points, Jan., Feb., Apr., Dec, Hervey; 

 Little Agar's Island, Nov., Collins. Common on exposed rocks in 

 shallow water all around the islands. A stout torulose trunk, 1-3 cm. 

 high, divides into several main axes, often unbranched, occasionally 

 rather freely branching; axes and branches terete, usually thickly set 

 with short, simple or forked proliferations, rarely over 1 mm. long; 

 leaves ovate or broadly lanceolate, margin irregularly undulate or 

 slightly dentate; occasionally forked, usually much crisped, midrib 

 distinct, cryptostomata small, scattered; vesicles spherical, smooth, 

 usually about 3 mm. diam., occasionally 5 mm., on filiform pedicels 

 usually shorter than the diameter of the vesicle, rarely with short tips. 

 Fructification of fihform branching receptacles, the main rachis usually 

 distinct, stouter than the radial branches, which may reach a length 

 of 2 cm. in the looser forms, but usually do not reach a length of 1 cm. ; 



