1843-1882] INSULAR FLORAS 483 



occasional immigration. The facts you give about certain Letter .366 

 plants, such as the heaths, 1 are certainly very curious. 1 

 thought the Azores flora was more boreal, but what can you 

 mean by saying that the Azores are nearer to Britain and 

 Newfoundland than to Madeira ? — on the globe they arc 

 nearly twice as far off. 2 With respect to sea currents, 1 

 formerly made enquiries at Madeira, but cannot now give 

 you the results ; but I remember that the facts were different 

 from what is generally stated : I think that a ship wrecked on 

 the Canary Islands was thrown up on the coast of Madeira. 



You speak as if only land-shells differed in Madeira and 

 Porto Santo : does my memory deceive me that there is a host 

 of representative insects? 



When you exorcise at Nottingham occasional means of 

 transport, be honest, and admit how little is known on the 

 subject. Remember how recently you and others thought 

 that salt water would soon kill seeds. Reflect that there is 

 not a coral islet in the ocean which is not pretty well clothed 

 with plants, and the fewness of the species can hardly with 

 justice be attributed to the arrival of few seeds, for coral islets 

 close to other land support only the same limited vegetation. 

 Remember that no one knew that seeds would remain for 

 many hours in the crops of birds and retain their vitality ; 

 that fish eat seeds, and that when the fish are devoured by 

 birds the seeds can germinate, etc. Remember that every 

 year many birds are blown to Madeira and to the Bermudas. 

 Remember that dust is blown 1,000 miles over the Atlantic. 

 Now, bearing all this in mind, would it not be a prodigy if an 

 unstocked island did not in the course of ages receive colonists 

 from coasts whence the currents flow, trees are drifted and 

 birds are driven by gales. The objections to islands being 

 thus stocked are, as far as I understand, that certain species 

 and genera have been more freely introduced, and others less 

 freely than might have been expected. But then the sea kills 

 some sorts of seeds, others are killed by the digestion of birds, 



1 In Hookers lecture he gives St. Dabeoc's Heath and Calluna 

 vulgaris as the most striking of the few boreal plants in the Azores. 

 Darwin seems to have been impressed by the boreal character of the 

 Azores, thus taking the opposite view to that of Sir Joseph. See 

 Letter 370, note I. 

 See Letter 368. 



