Page:Darwin Journal of Researches.djvu/418

This page has been validated.




Name of Island. Total No. of Species. No. of Species found in other parts of the world. No. of Species confined to the Galapagos Archipelago No. confined to the one Island. No. of Species confined to the Galapagos Archipelago, but found on more than the one Island.
James Island 71 33 38 30 8
Albemarle Island 46 18 26 22 4
Chatham Island 32 16 16 12 4
Charles Island 68 39 29 21 8
(or 29, if the probably imported plants be subtracted)

Hence we have the truly wonderful fact, that in James Island, of the thirty-eight Galapageian plants, or those found in no other part of the world, thirty are exclusively confined to this one island; and in Albemarle Island, of the twenty-six aboriginal Galapageian plants, twenty-two are confined to this one island, that is, only four are at present known to grow in the other islands of the archipelago; and so on, as shown in the above table, with the plants from Chatham and Charles Islands. This fact will, perhaps, be rendered even more striking, by giving a few illustrations:—thus, Scalesia, a remarkable arborescent genus of the Compositæ, is confined to the archipelago: it has six species; one from Chatham, one from Albemarle, one from Charles Island, two from James Island, and the sixth from one of the three latter islands, but it is not known from which: not one of these six species grows on any two islands. Again, Euphorbia, a mundane or widely distributed genus, has here eight species, of which seven are confined to the archipelago, and not one found on any two islands: Acalypha and Borreria, both mundane genera, have respectively six and seven species, none of which have the same species on two islands, with the exception of one Borreria, which does occur on two islands. The species of the Compositæ are particularly local; and Dr. Hooker has furnished me with several other most striking illustrations of the difference of the species on the different