328 Linncean Society. 



Meyen materially weakens his own argument in stating that he con- 

 siders the Gulf- weed {Sargassum bacciferum of Turner and Agardh), 

 and the Sargassum natans, or vulgare, specifically distinguished from 

 it by these authors, as one and the same species ; adding, that he 

 has observed among the Gulf weed all the varieties of Sargassum 

 vulgare described by Agardh ; and finally, that on the coast of Brazil 

 he has found what he regards as the Gulf-weed in fructification. 

 Now as Sargassum natans has been found fixed by a discoid base or 

 root, in the same manner as the other species of the genus, and as 

 according to Meyen the Gulf-weed has been found in fructification, 

 the legitimate conclusion from his statements seems to be, that this 

 plant is merely modified by the peculiar circumstances in which it 

 has so long been placed. I am not, however, disposed to adopt 

 Dr. Meyen's statement that he actually found the true Sargassum 

 natans, much less all its supposed varieties, mixed with the Gulf- 

 weed, having reason to believe that at the period of his voyage his 

 practical knowledge of marine submersed Algae was not sufficient to 

 enable him accurately to distinguish species in that tribe. It is not 

 yet known what other species of Sargassum are mixed with the 

 Gulf-weed, what proportion they form of the great band, nor in 

 what state, with respect to root or fructification, they are found ; 

 though, in reference to the questions under discussion, accurate in- 

 formation on these points would be of considerable importance. 



" That some mixture of other species probably exists may be in- 

 ferred even from Dr. Meyen's statement, and indirectly from that of 

 Lieut. Evans, who, in his communication published in Major Ren- 

 nell's invaluable work on the C'urrents of the Atlantic, asserts that 

 he found the Gulf- weed in fructification, which he compares with 

 that of Ferns, a statement which would seem to prove merely that 

 he had found along with the Gulf-weed a species of Sargassu7n with 

 dotted leaves, the real fructification of the genus bearing no resem- 

 blance to that of Ferns, though to persons slightly acquainted with 

 the subject the arranged dots on the leaves might readily suggest 

 the comparison. 



" With regard to the non-existence of roots in the Gulf-weed as 

 a proof of specific distinction, it is to be observed that the genus 

 Sargassum, now consisting of about sixty species, is one of the most 

 natural and most readily distinguished of the family Fucacea, and 

 that there is no reason to believe that any other species of the genus, 

 even those most nearly related to, and some of which have been 

 confounded with it, are originally destitute of roots ; though some 

 of them are not unfrequently found both in the fixed and in con- 

 siderable masses in the floating state, retaining vitality and probably 

 propagating themselves in the same manner (see Forskal, Fl. ^gypt.- 

 Arab. p. 192, n. 52). It is true indeed that a Sargassum, in every 

 other respect resembling Gulf- weed, has, I believe, not yet been found 

 furnished either with roots or fructification, neither Sloane's nor 

 Browne's evidence on this subject being satisfactory*. But the 



* See Sloane's Jam. i. p. 59. I have examined Sloane's spetiiiiens in 

 his Herliaiium ; they belong to Gulf-weed in its ordinary form, and are alike 



