To George Henry Kendrick Thwaites   7 February [1858]1

Down Bromley Kent

Feby. 7th

My dear Sir

I thank you heartily for your kind letter of Decr 28th & for all the information in your power on the resistance of plants to your climate, & on their acclimatisation on your different elevations.2

I am especially obliged for your remarks on the several species having alpine & lowland forms, & for what you mention about some having & some not having intermediate varieties.— I will quote this part of your note; for it was exactly a point on which I wanted information.3

You state that the latter ie lowland forms have much smaller flowers, & frequently more numerous; leaves, longer, narrower & less coriaceous. I copy this for there is often a mistake in “latters” & “formers”— If I do not hear to contrary, I will assume that this description does apply to the low-land forms.— I see you do not mention “hariness”,—a character usually given to alpine forms, but which Hooker has been looking into for me & disputes or rather overthrows.4

I was lately struck by a remark in U. States naturalist, namely that introduced or naturalised plants at first overrun the whole country, & then in some degree diminish in numbers.5 Do you know of anything like this in Ceylon, where you have so many naturalised plants?— I can see some likely causes of error in the foregoing remark, & yet the fact in itself seems probable.

How interesting it would be to cultivate some of the upland forms in the low country & trace probable changes in successive generations.—

With my very sincere thanks, Yours very truly | Ch. Darwin

1
The year is given by CD’s reference to Joseph Dalton Hooker’s ‘looking into’ the hairiness of alpine plants. This was a topic discussed by CD and Hooker in May 1857. The letter to Thwaites seems to have been written after that discussion rather than before.
2
Thwaites’s letter has not been found, but it apparently contained information cited by CD in Natural selection, p. 286: Mr. Thwaites, the curator of the Botanic Garden at Ceylon, whose accuracy is well known, writes to me, that he finds ‘that individuals of the same species are acclimatised to different elevations,—being more & more impatient of cultivation at any station, according as they have been transported to it, from stations of greater & greater altitude.’
3
Information on this point has not been located in Natural selection, Origin, or Variation.
4
See Correspondence vol. 6, letters to J. D. Hooker, [29 April 1857], [2 May 1857], and [3 May 1857]. CD discussed the hairs on alpine plants in Natural selection, p. 283.
5
CD had discussed this issue with Asa Gray (see Correspondence vol. 6).

Manuscript Alterations and Comments

0.2 Feby.] before del ‘Dec.’
4.2 overrun] above del ‘overun’
4.3 Do] after del ‘Have’

Please cite as “DCP-LETT-2211,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-2211