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 cireumstanced 
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 1 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 
