XX FLORA OP NEW ZEALAND. 



4. These three peculiarities are shared by all the islands in the south temperate zone (including 

 even Tristan d'Acunha, though placed so close to Africa), between which islands the transportation 

 of seeds is even more unlikely than between the larger masses of land. 



5. The plants of the Antarctic islands, which are equally natives of New Zealand, Tasmania, 

 and Australia, are almost invariably found only on the lofty mountains of these countries. 



Now as not only individual species, but groups of these, whether orders, genera, or their sub- 

 divisions, are to a great degree distributed within certain limits or areas, it follows that the flora of 

 every island or archipelago presents peculiarities of its own. Though an insular climate may 

 favour the relative abundance of individuals, and even species of certain Natural Orders, there is 

 nothing in the climate, or in any other attribute of insularity, which indicates the nature of the 

 peculiarity of endemic species. The islands of each ocean contain certain botanically alhed forms 

 in common, which are more or less abundant in them, and rarely or never found on the neigh- 

 bouring continents ; thus there are curious genera peculiar to the North Atlantic islands, others to 

 the North Pacific islands, others to those of the South Pacific, and others again to the Malayan 

 Archipelago; just as there are still others peculiar to the Antarctic islands, and many to New 

 Zealand, Fuegia, and Tasmania. 



Each group of islands hence forms a botanical region, more or less definable by its plants as 

 well as by its oceanic boundaries ; precisely as a continuous area like Australia or South Africa does. 

 There is however this difference, that whereas the Natural Orders that give a botanical character to 

 a continuous area of a continent or to a large island (as the Proteacece in South Africa or in New 

 Holland, and Coprosma in New Zealand) are numerous in species and often uniformly spread, — in 

 clusters of small islands, distant from continents, they are few in species, and the individuals are 

 scattered, appearing as if the vestiges of a flora which belonged to another epoch, and which is 

 passing away : this is perhaps a fanciful idea, but one which I believe to contain the germ of truth ; 

 for no Botanist can reflect upon the destruction of peculiar species on small islands (such as is now 

 going on in St. Helena amongst others), without feeling that, as each disappears, a gap remains,* 

 which may never be botanically refilled ; that not only are those links breaking by which he con- 

 nects the present flora with the past, but also those by which he binds the different members of the 

 vegetable kingdom one to another. It is not true in every sense that all existing nature appears to 

 the naturalist as an harmonious whole ; each species combines by its own peculiarities two or more 

 others more closely, and reveals their affinities more dearly, than any other does ; just as the flora 

 of an intermediate spot of land connects those of two adjacent areas better than any other locality 

 does. It is often by one or a very few species that two large Natural Orders are seen to be related ; 

 just as by a few Chilian plants the whole flora of New Zealand is connected with that of South 

 America. The destruction of a species must heuce create an hiatus in our systems, and I believe 

 that it is mainly through such losses that natural orders, genera, and species become isolated, that is, 

 peculiar, in a naturalist's eyes. 



To return to the distribution of existing species, I cannot think that those who, arguing for 

 unlimited powers of migration in plants, think existing means ample for ubiquitous dispersion, suffi- 

 ciently appreciate the difficulties in the way of the necessary transport. During my voyages amongst 

 the Antarctic islands, I was led, by the constant recurrence of familiar plants in the most inaccessible 

 spots, to reflect much on the subject of their possible transport ; and the conviction was soon forced 

 upon me, that, putting aside the almost insuperable obstacles to trans-oceanic migration between such 

 islands as Fuegia and Kcrguelen's Land, for instance (which have plants in common, not found else- 



