The Voyage of the Beagle

some respects confirming the results, plainly show that much remains to be done in the botany of this group: the Leguminosae, moreover, has as yet been only approximately worked out:--

                                                     Number of
                                                     Species
                                                     confined
                                                     to the
                  Number of   Number of              Galapagos
                  species     species      Number    Archipelago
         Total    found in    confined     confined  but found

Name Number other to the to the on more of of parts of Galapagos one than the Island Species the world Archipelago island one island

James 71 33 38 30 8 Albemarle 46 18 26 22 4 Chatham 32 16 16 12 4 Charles 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 Compositae, 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 Compositae are particularly local; and Dr. Hooker has furnished me with several other most striking illustrations of the difference of the species on the different islands. He remarks that this law of distribution holds good both with those genera confined to the archipelago, and those distributed in other quarters of the world: in like manner we have seen that the different islands have their proper species of the mundane genus of tortoise, and of the widely distributed American genus of the mocking-thrush, as well as of two of the Galapageian sub-groups of finches, and almost certainly of the Galapageian genus Amblyrhynchus.