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of Sargassum vulgave 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 Sargas- 

 sum 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 information 

 on these points would be of considerable importance. 



" That some mixture of other species probably exists may be 

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

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

 nelVs invaluable work on the Currents 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 Sargassum with dotted 

 leaves, the real fructification of the genus bearing no resemblance 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 Sar- 

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

 natural and most readily distinguished of the family Fucaceae, 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 



