12 Mindeskrift for J. Steenstrup. XXXII. 



B. Remarks upon the biology, affinities and origin of the Gulfweed. 



The Sargasso floats frequently so near the surface that tips of the leaves become 

 emerged when moved by the sea. 



The colour of the floating form is hght, hghter than that of the attached, varying 

 from brown to ohve-green, or often nearly ochreous; this apphes especially to the 

 young parts of the piants while the older are darker coloured. 



The Gulfweed is nearly always found in long narrow rows arranged in the direct- 

 ion of the wind, and at a right angle to the moving of the sea. Only more seldom 

 larger areas are found, sometimes reaching extensions of considerable width. ^) 



Common to the different forms of Gulfweed may be pointed out that they are 

 always sterile and, furthermore, that they usually appear of continuous growth. 



As to the first point, the lack of receptacles this is in accordance with the well- 

 known faet that floating and not attached algæ on the whole nearly always are sterile ; 

 that it also is so is actually pointed out by numerous investigators, for instance 

 TuENER^), G. Agardh^), Meyen*), Robert Brown''), G. von Martens^), Grunow^), 

 BouviER^), Sauvageau **), Gran^**) and severai others. 



However some few authors have expressed opposite views. In "Species Sargas- 

 sorum Australiæ", p. 106, J. Agardh writes: "radice instructam et fructiferam ad oras 

 Americæ foederatæ lectam habui, in rupibus extra New Foundland"^^) and on the 

 same page "In paucissimis speciminibus natantibus receptacula obvenire, certum 

 videtur". O. Kuntze, in his very unfortunate "Revision von Sargassum und das 

 sogenannte Sargasso-Meer", says, p. 197, that he has found "verschiedene Exemplare 

 auch mit Receptakel vom hohen Ocean". To this I wish to point out, that it may 

 happen that specimens with receptacles are found floating out at sea, but these are 

 not S. natans, but other forms, newly detached from the shores and carried out at sea. 

 Some few examples will be mentioned in the subsequent pages. 



') Gompare different works of O. Krummel quoted below, and also Holger Lassen in "Geo- 

 grafisk Tidsskrift", Bd. 12, Hefte 3/4.. 



Turner, D., Fuci, 1808, p. 103. 



Agardh, C, Species Algarum, 1823, p. 7. 



JVIeyen, i. J. F., Reise um die Erde, 1. Theil, 1834, p. 38. 



In Proceedings of tlie Linnean Soc. of London, vol. II, 1848—1865. p. 77. 



G. VON Martens, Die Tange (in "Die Preussische Expedition nach Ost-Asien", 1876 p. 7). 



In Askenasy, Algen (Forschungsreise S. M. S. "Gazelle", IV Theil, Botanik, p. 29). 



In Bullelin de l'Institut Océanograph., Monaco, 1907, No. 93, p. 35. 



In Comptes rendus des seances de la Société de Biologie, t. 62, p. 1082. 



In "The Depths of the Ocean", 1912, p. 336. 



That the plant should have been found "radice instructam" i. e. attached near New Found- 

 land seems so unlikely that 1 deem it unworthy of consideration. 



