CHAP. XII THE AZORES 261 



there will still remain a wonderfully rich ancj varied flora 

 to have been carried, by the various natural means above 

 indicated, over 900 miles of ocean, more especially as the 

 large proportion of species identical with those of Europe 

 shows that their introduction has been comparatively recent, 

 and that it is, probably (as in the case of the birds) still 

 going on. We may therefore feel sure that we have here 

 by no means reached the limit of distance to which plants 

 can be conveyed by natural means across the ocean ; and 

 this conclusion will be of great value to us in investigating 

 other cases where the evidence at our command is less 

 complete, and the indications of origin more obscure or 

 conflicting. 



Of the forty species which are considered to be peculiar 

 to the islands, all are allied to European plants except six, 

 whose nearest affinities are in the Canaries or Madeira. 

 Two of the Composite are considered to be distinct genera, 

 but in this order generic divisions rest on slight technical 

 distinctions ; and the Camjmnula vidalii is very distinct 

 from any other known species. With these exceptions, 

 most of the peculiar Azorean species are closely allied to 

 European plants, and are in several cases little more than 

 varieties of them. While therefore we may believe that 

 the larger part of the existing flora reached the islands 

 since the glacial epoch, a jDortion of it may be more ancient, 

 as there is no doubt that a majority of the species could 

 withstand some lowering of temperature ; while in such a 

 warm latitude and surrounded with sea, there would always 

 be many sunny and sheltered spots in which even tender 

 plants might flourish. 



Important Deduction from the Peculiarities of the Azor- 

 ean Fauna aiid Flora. — There is one conclusion to be 

 drawn from the almost wholly European character of the 

 Azorean fauna and flora which deserves special attention, 

 namely, that the peopling of remote islands is not due 

 so much to ordinary or normal, as to extraordinary and 

 exceptional causes. These islands lie in the course of the 

 south-westerly return trades and also of the Gulf Stream, 

 and we should therefore naturally expect that American 

 birds, insects, and plants would preponderate if they were 



