F. Børgesen: The Species of Sargassum. 



1. Sargassum natans (L.). ^) 



Fucus natans Linné, Species Plantarum 1753, T. II, p. 1160 ("Fucus 11 natans"). 



Esper, Icones Fucorum, I Theil, 1800, p. 49, tab. 23 (=var. ciliata). 



Vahl, M., Endeel kryptogamiske Planter fra St. Croix (Skrivter af Naturhistorie-Selskabet, 6te Bd., 



2det Hefte, 1802, p. 36). 

 Sargassum pelagium Rumphius, Herb. Amboinense, Vol. VI, 1750, p. 188, tab. 76 (here called Sarg. 



litoreum) = var. ciliata. 

 Fucus Sargasso Gmelin, Historia Fucorum, 1768, 



p. 92. 

 Fucus bacciferus Turner, Fuci, vol. I, 1808, pp. 103 



—108, pi. 47. 

 Sargassum bacciferum C. Agardh, Species Algarum, 



vol. I, 1821, p. 6. 

 J. Agardh, Species Algarum, vol. I, 1848, p. 344. 



-- , Species Sargassorum Australiæ, 1889, 



p. 106. 

 Grunow in AsKENASY, Algen (Forschungsreise S. 

 M. S. Gazelle, IV. Theil, 1888, p. 29)'^). 



As is generally the case in respect to Lin- 

 nean diagnoses these are very brief, and Fucus 

 natans is only described as follows (I. c): 



') In Revisio generum plantarum, pars II, 

 1891, p, 915, O. KuNTZE writes: "Anstatt Sargas- 

 sum bacciferum Ag. (Turn. 1802) bez. S. vulgare Kg. 

 em. O. K. ist iibrigens Sargassum natans R. Br. 

 (L. 1753) zu schreiben; auch Miquel wendetc 

 diesen Namen an." When I have not added the 

 name of Robert Brown after the combination 

 Sargassum natans it is because the Sargassum natans 

 of Robert Brown (in Proceedings of the Linnean 

 Society of London, vol. II, 1855, p. 77) is Fucus 

 natans of Tvr^eb. = Sargassum vulgare C. Ag., and 

 not this species. Robert Brown says himself, and 

 very clearly so, f. i. p. 78: ^^ Sargassum natans, or 

 vulgare," and, opposite to it: "the Gulfweed [Sar- 

 gassum bacciferum of Turner and Agardh)". And 

 on the next page 79 is also mentioned that the 

 leaves of the Gulfweed are destitute of the tricho- 

 stomata, while such are constantly present in S. 

 natans. Where Miquel used the combination S. 

 natans 1 have not succeeded in finding. 



Besides Kerner, in "Pflanzenleben", 2ter Bd., 1891, p. 622, has written Sargassum natans 

 beneath a good illustration of the var. ciliata of this epecies. 



*) How far the Sargassum Chamissonis Kiitz. from the Pacific Ocean belongs to this species or 

 not I do not know; it resembles (comp. Kiitz., Tab. phycoL, vol. XI, tab. 11) S. natans var. typica 

 in having vesicles without a filiform appendage at their top but differs by its flat stem (comp. also 

 KiJTziNG, Spec. Alg., p. 610). According to Reinbold (in Weber-van Bosse, Liste des Algues du 

 Siboga, I, 1913, p. 164) there does not seem to be any difference between the forms of Sargassum 

 natans from the Pacific and the Atlantic Ocean. 



Fig. 3. Sargassum natans (L.). 



Type-specimen from the Linnean Herbarium. 



The plant is partly covered with Membrani- 



pora tuberculata. 



