242 Dr. J. D. Hooker on the Vegetation 



of tliese orders will be recognised as forming a great part of the vegetation of 

 every tropical country, except the yimaranthacece, which however find their 

 maximum on the west coast of South America. Hence it is not to the preva- 

 lence of any particular natural order, or the undue number of species contained 

 in any one, that the Galapagos owe their extraordinary amount of novelty. All 

 the general features of a tropical vegetation are retained, and even the genera to 

 a great extent, but the change is in the species, of which one half are confined 

 to that archipelago ; and this peculiarity in species not only relates to the 

 difference existing between the Galapagos and the mainland of America, of 

 which it is a botanical province, but to the separate islets of the archipelago, 

 which, as Mr. Darwin aptly remarks, should be called " a group of satellites, 

 physically similar, organically distinct, yet intimately related to each other, 

 and all related in a marked though much less degree to the great American 

 continent." 



GLUMACEiE. — This somewhat artificial group, including Graminew, Cype- 

 racece and Junci, has been defined by Humboldt as including the majority of 

 Monocotyledones in all latitudes. In the tropics of America these collectively 

 form xx of the flowering plants, which is precisely the Galapageian proportion, 

 and one that would not be expected if the fewness of the Monocotyledones pre- 

 viously alluded to be borne in mind. Two conclusions may be drawn from this, 

 that this paucity is owing to the scarcity of petaloid families, and that the fewness 

 of Graminece, to which I shall next refer, is compensated by the Cyperaceoe. 



Gramine^. — This order forms little more than ^o of the Phsenogamic flora, 

 the smallest proportion I have obtained from any country. This is the more 

 remarkable, as nearly three-fourths are peculiar, proving that the order, though 

 having many species which are well adapted for transport, has not sent its 

 colonists to the Galapagos in the same proportion as it has to other countries ; 

 as to the Sandwich Islands for instance, three-fourths of whose grasses are those 

 of other countries. This paucity is further conspicuous from the islands within 

 the tropics being richer in Graminece than the continents, where they do not 

 form more than -j^, whilst in the Sandwich Islands they amount to ^, and in 

 the Society's, lying in the same longitude and equidistant from the equator on 

 the opposite side, also ^, which is the Cape Verd proportion also ; a singular 

 concurrence, considering that in all three localities the species are very dif- 



