Comments on AG's memoir on Japanese plants [see 2599]; relationship of Japanese flora to N. American.
Down Bromley Kent
My dear Gray
I have just finished your Japan memoir & I must thank you for the extreme interest with which I have read it. It seems to me a most curious case of distribution & how very well you argue & put the case from analogy on the high probability of single centres of creation. That great man Agassiz, when he comes to reason seems to me as great in taking a wrong view as he is great in observing & classifying.
One of the points which has struck me as most remarkable & inexplicable in your memoir is the number of monotypic (or nearly so) genera amongst the representative forms of Japan & N. America. And how very singular the preponderance of identical & representative species in Eastern compared with Western America.—
I have no good map showing how wide the moderately low country is on the west side of the Rocky Mountains: nor of course do I know whether the whole of the low Western territory has been botanised; but it has occurred to me looking at such maps as I have, that the Eastern area must be larger than western which would account to certain small extent for preponderance on Eastern side of the representative species. Is there any truth in this suspicion? Your memoir sets one marvelling & reflecting.— I confess I am not able quite to understand your geology at p 447, 448; but you would probably not care to hear my difficulties. & therefore I will not trouble you with them.
I was so grieved to get a letter from Dana at Florence, giving me a very poor (though improved) account of his health.
Believe me, my dear Gray | Yours very sincerely | C. Darwin
What an admirable memoir on the distribution of Australian plants is that by Hooker!
- f1 2645.f1The year is given by the references to Gray 1859 and Hooker 1859.
- f2 2645.f2Gray had sent CD a copy of his description of the plants collected by Charles Wright in Japan (Gray 1859) (see Correspondence vol. 7, letter to Asa Gray, 24 December ). Several months earlier CD had read proof-sheets of the concluding section of the paper, sent to him by Joseph Dalton Hooker (see Correspondence vol. 7, letter to J. D. Hooker, 11 May ). There is a copy of the work in the Darwin Pamphlet Collection--CUL.
- f3 2645.f3In his paper, Gray discussed the views that had been put forward to explain the distribution of species. He contrasted the opinion of Louis Agassiz that species had originated in great numbers in the geographical area they now inhabit with the theory that each species had originated in a single place from which it dispersed. Gray gave his reasons for supporting the latter view and mentioned CD's contribution to this topic. See Gray 1859, pp. 445--8.
- f4 2645.f4CD felt that there was insufficient geological evidence for Gray to suggest that there had been a post-glacial warm period during which Asian and North American plants had mingled. CD described his objections in detail in letters to Gray and to Hooker in 1859. See Correspondence vol. 7, letters to J. D. Hooker, 11 May  and 28 [December 1859], and to Asa Gray, 11 November  and 24 December . Gray had based his geological arguments on information given to him by his friend James Dwight Dana (Gray 1859, p. 449).
- f5 2645.f5Dana was in Italy convalescing from a breakdown in his health. He had written to CD in December 1859 (see Correspondence vol. 7, letter to Charles Lyell, 29 [December 1859]). See also letter to T. H. Huxley, 1 January .
- f6 2645.f6Hooker 1859. See letter to J. D. Hooker, 3 January .