To Asa Gray 25 April 
Down Farnborough Kent1
My dear Sir
I hope that you will remember that I had the pleasure of being introduced to you at Kew.2 I want to beg a great favour of you, for which I well know I can offer no apology. But the favour will not, I think, cause you much trouble & will greatly oblige me. As I am no Botanist, it will seem so absurd to you my asking botanical questions, that I may premise that I have for several years been collecting facts on “Variation”, & when I find that any general remark seems to hold good amongst animals, I try to test it in Plants.—
I have the greatest curiosity about the alpine Flora of the U.S., & I have copied out of your Manual the enclosed list;3 now I want to know whether you will be so very kind as to append from memory (I have not for one instant the presumption to wish you to look to authorities) the other habitats or range of these plants: appending “Indig.” for such as are confined to the mountains of the U.S.— “Arctic Am.” to such as are also found in Arctic America.— “Arctic Eu.” to those also found in Arctic Europe:—& “Alps” to those found on any mountains of Europe.—“& Arct. Asia” I have compared the list with the plants of Britain, but I am of course afraid of trusting to myself, from ignorance of synonyms &c.—4
I see that there are 22 species common to the White Mts & the Mts of New York, will you tell me about how wide a space of low land, on which these alpine plants cannot grow, separates these mountains: I can hardly judge from the height not being marked on the prolongation of the mountains of Vermont.—5
I venture to ask for one more piece of information, viz. whether you have anywhere published a list of the phanerogamic species common to Europe, as has been done with the shells & Birds, so that a non-Botanist may judge a little on the relationship of the two floras. Such a list would be of extreme interest for me in several points of view & I should think for others. I suppose there would not be more than a few hundred out of the 2004 species in your Manual. Should you think it very presumptuous in me to suggest to you to publish (if not already done) such a list in some Journal?— I would do it for myself, but I shd assuredly fall into many blunders. I can assure you, that I perceive how presumptuous it is in me, not a Botanist, to make even the most trifling suggestion to such a Botanist as yourself; but from what I saw & have heard of you from our dear & kind friend Hooker, I hope & think that you will forgive me, & believe me, with much respect, | Dear Sir | Your’s very faithfully | Charles Darwin
Is collecting facts on variation; questions AG on the alpine flora of the U. S.
Sends a list of plants from AG’s Manual of botany  and asks him to append the ranges of the species.
Please cite as
Darwin Correspondence Project, “Letter no. 1674,” accessed on 25 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-1674