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Show 412 ISLAND LIFE. (PART II. fifty are endemic, twenty-two are Asiatic but ~o.t. Af:ican, while twenty-eight are African but not Asiatic. T.h1s 1mphe~ that t?e more ancient connection has been on tho s1de of Afnca, while · a more recent immigration, shown by identity of species, has come from the side of Asia; and it is probable that when the flora of Madaaascar is more thoroughly worked out, the same, or a still greater African preponderance, will be found in that island. A few Mascarene genera are found elsewhere only in South America, Australia, or Polynesia ; and there are also a considerable number of genera vd1ose metropolis is South America, but which are represented by one or more species in Madagascar, and by a single often widely distributed species in Africa. This fact throws light upon the problem offered by those mammals, reptiles, and insects of Mada,gascar which now have their only allies in South America, since the t\vo cases would be exactly parallel were the African plants to become extinct. Plants, ho\vever, are undoubtedly more long-liveJ specifically than animals-especially the more highly organised groups, and are less liable to complete extinction through the attacks of enemies or through changes of climate or of physical geography; hence we find comparatively few cases in which groups of 1\1adagascar plants have their only allies in such distant regions as America and Australia, w bile such cases are numerous among animals, owing to the extinction of the allied forms in intervening areas, for which extinction, as we have already shown, ample cause can be assigned. o~trious Relations of Mascarene Plants.-Among the I"Uri0uS affinities of Mascarene plants we have culled the following from Mr. Baker's volume. Trochetia, a genus of Sterculiacem, bas four species in Mauritius, one in Madagascar, and one in the remote island of St. Helena. Mathurina, a genus of Turneracere, consisting of a single species peculiar to Rodriguez, has its nearest ally in another monotypic genus, Erblicl1ia, confined to Central America. Siegesbeckia, one of the Compositre, consists of two species, one inhabiting the Mascarene islands, the other Peru. Labourdonasia, a genus of Sapotacere, has two species in Mauritius, one in Natal, and one in Cuba. Nesogenes, belonging to the verbena family, has one spec1es m CHAP. XIX.] '!'liE MADAGASCAR GROUP. 413 Rodriguez and one in Polynesia. Mespilodaphne, an extensive genus of Lauracere, has six species in the Mascarene islands, and all the rest (about fifty species) in South America. N epenthes, the well-known pitcher plants, are found. chiefly in the Malay Islands, South China, and Ceylon, with species in the Seychelles Islands, and in Madagascar. Milia, a large genus of Liliacere, is exclusively American, except one species found in Mauritius and Bourbon. Agauria, a genus of Ericacere, is confined to the Mascarene islands and the Camaroon Mountains in West Africa. An acacia, found in Mauritius and Bourbon (A. heterophylla), can hardly be separated specifically from Acacia koa of the Sandwich Islands. The genus Pandanus, or screw-pine, has sixtee~ species in the three islandsMauritius, Rodriguez, a~d the Seychelles-all being peculiar, and none ranging beyond a single island. Of palms there are fifteen species belonging to ten genera, and all the.se genera are peculiar to the islanJs. We have here ample evidence that plants exhibit the same anomalies of distribution in these islands as do the animals, though in a smaller proportion; w bile they also exhibit some of the transitional stages by which these anomalies have, in all probability, been brought about, rendering quite unnecessary any other changes in the distribution of sea and land than physical and geological evidence warrants.1 1 It may be interesting to botanists and to students of geographical distribution to give here an enumeration of the endemic genem of the Flora of the Mauritius and the Seychelles, as they are nowhere separately tabulated in that work. Aphloia (Bixucero) ................. 1 sp., a shrub, Maur., Rod., Sey., also Madagascar. Medusagyne (Ternstromiacero ) .. 1 sp., a shrub, Seychelles. Astiria ( Sterculiacero) ............ 1 sp., a shrub, Mauritius. Quivisia (Meliacero) ............... 3 sp., shrubs, Mauritius (2 sp. ), Rodriguez (1 sp. ), also Bourbon. Cossignya (Sapindacero) ....... 1 sp., a shrub, Mauritius, also Bourbon. Hornea , ......... 1 sp., a shrub, Mauritius. Stadtmannia , ........ . 1 sp., a shrub, Mauritius. Doratoxylon , ......... 1 sp., a shrub, Mauritius and Bourbon. Gagnebina ( Leguminosro) ........ 1 sp., a shrub, Mauritius, also Madagascar. Roussea (Saxifragacero) .......... 1 sp., a climbing shrub, Mauritius and Bourbon. |