512 ISLAND LIFE 



persal over seas and oceans. This is especially well shown 

 by -the case of the Azores, where no less than 400 out of a 

 total of 478 flowering plants are identical with European 

 species. These islands are more than 800 miles from 

 Europe, and, as we have already seen in Chapter XII., 

 there is no reason for supposing that they have ever been 

 more nearly connected with it than they are now, since an 

 extension of the European coast to the 1,000-fathom line 

 would very little reduce the distance. Now it is a most 

 interesting and suggestive fact that more than half the 

 European genera Avhich occur in the Australian flora occur 

 also in the Azores, and in several cases even the species are 

 identical in both.^ The importance of such a case as this 

 cannot be exaggerated, because it affords a demonstration 

 of the power of the very plants in question to pass over 

 wide areas of sea, some no doubt wholly through the air, 

 carried by storms in the same way as the European birds 

 and insects which annunlly reach the Azores, others by 

 floating on the waters, or by a combination of the two 

 methods ; while some may have been carried by aquatic 

 birds, to whose feathers many seeds have the power of 

 attaching themselves, and some even in the stomachs of 

 fruit or seed eating birds. We have in such facts as these 

 a complete disproof of the necessity for those great changes 

 of sea and land which are continually appealed to by those 

 who think land-connection the only efficient means of ac- 

 counting for the migration of animals or plants ; but at the 

 same time we do not neglect to make the fullest use of 

 such moderate changes as all the evidence at our com- 

 mand leads us to believe have actually occurred, and 

 especially of the former existence of intermediate islands, 

 so often indicated by shoals in the midst of the deepest 

 oceans. 



Means hy vjJiich Plants have migrated from North to 

 South. — But if plants can thus pass in considerable numbers 

 and variety over wide seas and oceans, it must be yet more 

 easy for them to traverse continuous areas of land, where- 

 ever mountain-chains offer suitable stations at moderate 



^ Hooker, OiitJic Flora of Australvi, p. 95. — H. C. Watson, in GoJi«au's 

 Azores, pp. 278-286, 



