8 



Mindeskrift for J. Steenstrup. XXXII. 



"Fucus caule tereti ramosissimo, foliis lanceolato-serratis, fructificationibus globo- 



sis ') pedunculatis subaristatis. Habitat in Pelago libera natans. nec radicatus. Vege- 



tabile ni fallor, inter omnia in orbe, numerosissimum". 



"Flora Zeylanica" is the first quotation of Linné. 

 Here (p. 184) we find the following diagnosis: "Fucus 

 caule tereti ramosissimo, frondibus lanceolato-lineari- 

 bus serratis, fructificationibus globosis pedunculatis 

 folioque umbilicatis," hence about the same as in 

 "Species Plantarum". He quotes, also, "Hortus CHf- 

 fortianus", where on page 478 the same diagnosis 

 as in "Flora Zeylanica" recurs. Besides Linné does 

 make some remarks upon its occurrence: "Crescit 

 in omnibus fere rupibus aqua marina opertis circa 

 Jamaicam, aliisque Americæ pluribus, unde a fluctibus 

 abripitur, magnamque partem maris Americani bore- 

 alis implet, ut pratum viride diceret spectator remotus. 

 From this it is clear that Linné refers to the 

 floating Sargassum in the Sargasso Sea, but whether 

 Linné wrote his diagnosis from specimen of S. nataiis 

 or from S. Hy- 

 strix remains 

 conjectural;it 

 must be ad- 

 mitted, how- 

 ever, that the 



description of the leaves "lanceolato-linearibus" 



agrees best with S. natans of which the leaves 



are very narrow. 



But here the Linnean Herbarium does render 



some assistance, since the finest specimen in his 



herbarium represents a form most closely ap- 



proaching the figure given by Turner (1. c). 

 The writer takes the opportunity to thank 



most cordially Mr. Daydon Jackson, General 



Secretary of the Linnean Society, from whom 



were received excellent photos of the three spe- 



cimens of Sargassum natans found in Linnné's 



Fig. 4. Sargassum natans (L.) var. 



typica. Branch with gas-bladders in 



various state of development. 



(About '/s magnified). 



Fig. 5. Sargassum natans (L.) var. typica. 



\ somewliat broad-leafed form and witli 



rather short-stalked vesicles. 



(About Ve magnified.) 



') Linné was of the opinion that the vesicles were fruits! 



