Page:Journal of botany, British and foreign, Volume 9 (1871).djvu/60

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country. No fewer than twenty-one species inhabit these two countries, of whicli thirteen are common to both ; but, what is very remarkable, the intervening island of Java contains but one representative of the genus, and that a totally different species from either the Bornean or the Ma- layan ; thus confirming the fact first brought to light by the Dutch natu- ralists, of the close biological relationship between the two former locali- ties, to the exclusion of Java. Only one species has a wide range, the N. pk^llamphora, which extends from Sumatra to Borneo, Amboyua, China, etc., but is absent from the island of Java.

Proceeding from the Malayan islands westwards, we find one species in east Bengal, more allied to the Javanese than to any other ; another in Cey- lon, the old N. dlstillatoria of Linnaeus (a name long usurped in our gardens by the Bengal plant), which presents the first departure from the typical structure of the genus, having a spreading paniculate inflorescence; a character shared by those in Madagascar and the Seychelles. Proceeding fuilher west to the African islands, we find still further deviations from the type, which now extend to the structure of the seed and fruit ; for whereas all the eastern species have very long appendages to the seed, which are no doubt instrumental in its dispersion, these appendages are very short in the Madagascar species, and are wholly absent in the Sey- chelle one ; which thus presents a case analogous to that of the preva- lence of wingless insects on oceanic islets. Lastly, the Seychelle Islands species further difi'ers from all others in the structure of its ovary and capsule.

To sum up, deviation from the type of the genus commences on the western confines of the principal centre of its distribution, namely in Cey- lon ; and the initial deviation, that met with in the Ceylon species, is the slightest, but is propagated (so to speak) westwards, equally characterizing the two African islands Pitcher-plants, which again deviate still further from the type ; the maximum deviation, however, occurs, not in the great sub-continental Island of Madagascar, where the endemic species has a considerable range ; but in the ver^^ small oceanic Archipelago of the Sey- chelles, Avhere the only native species is confined to the one mountain summit of one island of the group !

The only other fact that struck me as bearing upon this subject of dis- tribution is, that though present in the Seychelles, the genus Nepenthes is absent from the Mascarene group (Mauritius, Bourbon, and Rodrigues). This is only one instance of the broad distinction that exists between the vegetation of these Archipelagos, and which is in some way connected with the fact that the Mascarene group is volcanic, the Seychelles group formed of granite and quartz. Coincident and perhaps co-ordinate Avith these phenomena of plant distribution, geographical position, and geological structure, are the facts that the flora of the Seychelle Archipelago is more Asiatic, and the florulfe of its several islets very uniform ; whilst the florulse of the islets of the Mascarene Archipelago differ wonderfully, and in their totality are more African than Indian. The flora of the Mascarene group may hence be regarded either as a very ancient outlying province of the African, or as consisting of a more modern assemblage of plants, de- rived at various periods from Africa, but subsequently much altered by causes operating in the several islets ; or more probably its peculiarities are attributable to both causes. Long as the Slascarene and Seychelle islets have been colonized, under Dutch, French, and English rule, their

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