of the Galapagos Archipelago, 239 



explored, (and whose mountains, which attain 8000 feet, have not been 

 ascended above 1000 feet,) are known to yield upwards of 300 species on a 

 .soil quite as sterile as that of the Galapagos, whilst the Sandwich and Society- 

 groups are much richer, though further detached from any continent. What 

 however is known suffices to institute a comparison between the vegetation of 

 this group and that of the neighbouring continent and with that of other 

 tropical islets ; a subject which divides itself into the following branches : — 



I. As the most important considerations regarding the vegetation of a 

 country relate to its most characteristic natural orders, I shall first offer a 

 few observations upon the number of species contained in the different fami- 

 lies, and on the proportion which each of the principal ones bears to the whole 

 Flora, and then compare the results with what have been obtained on the 

 neighbouring continent, or on other islands somewhat similarly circumstanced 

 with the Galapagos. 



II. Here, as in other countries, the vegetation is formed of two classes of 

 plants ; the one peculiar to the group, the other identical with what are found 

 elsewhere. In this there are even indications of the presence of two nearly 

 equal Floras, an indigenous and introduced, and these are of a somewhat 

 different stamp ; for the introduced species are for the most part the plants of 

 the West Indian islands and of the lower hot parts of the South American 

 coast ; whilst the peculiar Flora is chiefly made up of species not allied to the 

 introduced, but to the vegetation which occurs in the Cordillera or the extra- 

 tropical parts of America. 



III. In the third place, I shall allude to the most singular feature in the 

 botany of the group, the unequal dispersion of the species, the restriction of 

 most of them to one islet, and the representation of others by allied species in 

 two or more of the other islets. 



The first peculiarity in the Flora of the Galapagos which demands attention 

 is the paucity of Monocotyledonous plants, which hardly equal ^ of the Dicoty- 

 ledons. In all tropical countries the Monocotyledones bear a smaller proportion 

 to the Dicotyledones than is found in the temperate or colder latitudes : Baron 

 Humboldt has stated this proportion to be ^ of the vegetation for the tropics 

 of the new world, and Mr. Brown \ for that of the old. As however that of 

 Baron Humboldt was obtained from materials collected partly from very 



