THE ALGAE OF BERMUDA. 



81 



p. 54; Fucus natans Linnaeus, 1753, p. 1160; Fuc us baccif ems Turner, 

 1808, p. 105, PI. XLVII. Stem long, slender, smooth, with more or 

 less distant similar branches; leaves long, slender, linear, with many 

 sharp teeth, cryptostomata wanting or inconspicuous ; vesicles numer- 

 ous, on long slender pedicels, and usually with a filiform prolongation; 

 fructification unknown; unattached, floating near the surface of the sea, 

 forming loose floating patches, or strips in the line of the direction of 

 the wind; in quiet water the tips of the leaves project above the water, 

 like bristles; drifting ashore at all times, and in case of storms in 

 immense quantities, and used as a fertilizer. It inhabits a large area 

 in the North Atlantic, within a boundary formed by the Gulf Stream 

 and its subsidiaries, reaching the coast of Europe, turning south and 

 then west to its origin in the Gulf of Mexico. It has an active vege- 

 tative growth, the lower part of the stem decaying, increasing the 

 number of individuals by fragmentation. It has never been found 

 attached nor in fruit, and though in all probability originally derived 

 from an attached form, it now appears to be so changed by its mode of 

 life that it is unlikely that the attached species from which it was 

 derived will ever be certainly determined. 10 



In several instances there have been reports of finding this species 

 in fruit, but in each case when examined there are circumstances 

 leading to the conclusion that the plant observed belonged to some 

 other species. 



2. S. FLUITANS Borgesen, 1914a, p. 222; P. B.-A., No. 2177; S. 

 Hystrix var. fluitans Borgesen, 1914, p. 11, fig. 8. Stem rather stout, 

 mostly smooth, occasionally with a few spines, much branched; 

 leaves lanceolate to ovate-lanceolate, thickish, cryptostomata present 

 but not conspicuous, teeth short and triangular; vesicles spherical, 

 about 5 mm. diam., short-pedicelled, usually without prolongations; 

 fructification unknown. Floating with S. natans, but less abundant; 

 propagated by fragmentation only. It may be derived from S. 

 Hystrix J. Ag., but if so the derivation is remote and the differ- 

 entiation considerable. Both S. natans and S. fluitans are lighter in 

 color than the attached species. 



3. S. LINIFOLIUM (Turn.) Agardh, 1848, p. 18; P. B.-A., No. 2179; 

 Fucus HnifoUus Turner, 1811, p. 64, PI. CLXVIII. On rocks above 

 and below Flatts bridge and at other points in Harrington Sound and 

 in Hamilton Harbor, Hervey, Collins. From a common base but with- 

 out any general trunk arise several axes with more or less frequent 



10 For fuller discussion of floating Sargassum, see Collins, 1917. 



