18671882] EVOLUTION OF ANGIOSPERMS 



analogous cases on the mountains of Madagascar. 1 ... I Letter 398 

 think that you ought to allude to these cases. 



I most fully agree that no problem is more interesting 

 than that of the temperate forms in the southern hemisphere, 

 common to the north. I remember writing about this after 

 Wallace's book appeared, and hoping that you would take it 

 up. The frequency with which the drainage from the land 

 passes through mountain-chains seems to indicate some 

 general law viz., the successive formation of cracks and 

 lines of elevation between the nearest ocean and the already 

 upraised land ; but that is too big a subject for a note. 



I doubt whether any insects can be shown with any 

 probability to have been flower feeders before the middle 

 of the Secondary period. Several of the asserted cases have 

 broken down. 



Your long letter has stirred many pleasant memories of 

 long past days, when we had many a discussion and many 

 a good fight. 



To J. D. Hooker. Letter 



Down, Aug. 2ist, 1 88 1. 



I cannot aid you much, or at all. I should think that no 

 one could have thought on the modification of species without 

 thinking of representative species. But I feel sure that no 

 discussion of any importance had been published on this 

 subject before the Origin, for if I had known of it I should 

 assuredly have alluded to it in the Origin, as I wished to 

 gain support from all quarters. I did not then know of 

 Von Buch's view (alluded to in my Historical Introduction 

 in all the later editions). Von Buch published his Isles 

 Canaries in 1836, and he here briefly argues that plants 

 spread over a continent and vary, and the varieties in time 

 come to be species. He also argues that closely allied species 

 have been thus formed in the separate valleys of the Canary 

 Islands, but not on the upper and open parts. I could lend 

 you Von Buch's book, if you like. I have just consulted 

 the passage. 



I have not Baer's papers ; but, as far as I remember, the 

 subject is not fully discussed by him. 



1 See Letter 397, Note 2. 



