Linneean Society. 327 



grumos^ farctis.— Triuriaceae in locis humidis umhrosis sylvarum infer- 

 tropicarum Asiee et Americw epigea. 



1 TRiuRiEas. Perianthii laciniae appendice lineavi, aestivatione spiraliter 

 "torta etinclusa, detnum exserta, munit^ Stylus cum pvanog.bboso 



lateraliter continuus. Antherarum lobi disjuncti, smguli 2-locellavi. 



Perianthii laciniffi 3. Stamina 3 1- Triuris. 



Perianthii lacinise 6. Stamina ignota 2. Hexuris. 



2 SciAPHiLE^E. Perianthii lacinias ecaudatse. Styhis fere basilaris. An- 

 therarum lobi confluentes et inde 4-locellati, rim^ transversali v. ver- 

 ticali bivalvatim hiantes. 



Perianthii lacinise 4. Stamina 2 3. Soridium. 



Perianthii lacini^ 6. Stamina 6 4. Sciaphila. 



Perianthii laciniae 8. Stamina 4 5. Hyahsma., 



May 7.— R. Brown, Esq., President, in the Chair. 

 Read a letter, dated May 19. 1845, addressed by the President to 

 Admiral Sir Francis Beaufort, for communication to Baron Alexander 

 von Humboldt, " On the Origin and Mode of Propagation of the 

 Gulf- weed." The letter is as follows :— 

 " Mv dear Captain Beaufort, 

 " I am vexed to have kept Baron Humboldt's letter so long, and 

 now in returning it, that it should be accompanied by so little satis- 

 ^acIJy informarion on the only one of its queries with which I could 

 have been supposed to deal, namely that which relates to the origin 

 and mode of propagation of the Gulf- weed. ,,,,.,.„ , 



.' Sn this subject it appears that M. de Humboldt (in his Personal 

 Narrative) first supported the more ancient notion, that the plant 

 orio-inally fixed, was brought with the stream from the Gulf of 

 Florida and deposited in what Major Rennell calls the recipient of 

 tha st/eam. More recently, however. Baron Humboldt has adopted 

 Se opinion*, also held b/ several travellers, that the Gulf-weed 

 orio-inates and propagates itself where it is now found. To the 

 adoption of this view it appears that he has been led chiefly by the 

 observations of the late Dr. Meyen, who in the year 1830 passed 

 through a considerable portion of the great band of Gulf-weed, and 

 who ascertained, as he states, from the examination of several thou- 

 Tand specimens, that it was uniformly destitute both of root and 

 fructification; he concludes, therefore, that the plant Fopagates 

 itself solely by lateral branches : he at the same time demes that it 

 is^rought from the Gulf of Florida, as. according to his own obser- 

 vation, it hardly exists in that part of the ^l'^^"^ ^^^'^^Y'lf^ 

 land, though found in extensive masses to the westward I have 

 here to remlrk that, as far as relates to the absence of root and fruc- 

 tification. Meyen has only confirmed by actual °Y^':tM7 Turner 

 been previously stated by several authors, particularly by Mr- Turner 

 (in h?s 'Historia Fucorim.' vol. i. p. 103. published in 1808), and 

 Agardh (in his ' Species Algarum,' p. 6, published in 1820). But 

 • Histoire de la Geographic du Nouveau Continent, vol. iii. p- 73, and 

 Meyen, Reise, vol. i. p. 36-9. 



