Alfred Russel Wallace 



To Sir W. Thiselton-Dyer 



Pen-y-hryn, St. Peter's Road, Croydon. January 7, 1881. 



Dear Mr. Thiselton-Dyer, — If I had had your lecture 

 before me when writing the last chapters of my book I should 

 certainly have quoted you in support of the view of the 

 northern origin of the Southern flora by migration along 

 existing continents. On reading it again I am surprised to 

 find how often you refer to this ; but when I read it on its 

 first appearance I did not pay special attention to this point 

 except to note that your views agreed more closely with those 

 I had advanced, derived from the distribution of animals, 

 than those of any previous writer on botanical distribution. 

 When, at a much later period, on coming to the end of my 

 work, I determined to give a chapter to the New Zealand 

 flora in order to see how far the geological and physical rela- 

 tions between New Zealand and Australia would throw light 

 on its origin, I went for my facts to the works of Sir Joseph 

 Hooker and Mr. Bentham, and also to your article in the 

 " Encyclopaedia Britannica," and worked out my conclusions 

 solely from these, and from the few facts referring to the 

 migration of plants which I had collected. Had I referred 

 again to your lecture I should certainly have quoted the cases 

 you give (in a note, p. 431) of plants extending along the 

 Andes from California to Peru and Chile, and vice versa. 

 Whatever identity there is in our views was therefore arrived 

 at independently, and it was an oversight on my part not 

 referring to your views, partly due to your not having made 

 them a more prominent feature of your very interesting and 

 instructive lecture. Working as I do at home, I am obliged 

 to get my facts from the few books I can get together ; and I 

 only attempted to deal with these great botanical questions 

 because the facts seemed sufficiently broad and definite not to 

 be much affected by errors of detail or recent additions to our 



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