RECORD: Darwin, C. R. 1854.03.26. Asa Gray in letter to Hooker uses same argument as Dana. CUL-DAR205.2.102. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 5.2022. RN1
NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volume CUL-DAR205.2 contains notes on means of distribution.
The brown crayon number '18' indicates that this document was filed by Darwin in his portfolio for the subject of Migration.
[102]
18
Asa Gray in letter to Hooker, uses same argument as Dana, about representative species, being due to similarity of Climate: I shd say if so, there ought to have been much more resemblance ie in all the species: but many facts show that conditions will not account for differences in productions, ∴ he will admit Empetrum rubrum & nigrum as distinct, but not if they grew together, or if we cd trace either along the Andes to Colombia or Mexico. Thinks, where 2d representative forms keeping characters distinct meet we cannot decide whether its origins distinct or are varieties from a common form. Asa Gray speculates on the effects of crossing obliterating varieties.
If these views hold with species, they shd hold with higher groups.
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March 26 1854
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 25 September, 2022