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Darwin Correspondence Project

From J. S. Henslow   2 August 1856

Hitcham, Bildeston, Suffolk.

2 Aug 1856

My dear Darwin,

I go to town on Tuesday & on to Cheltenham on Thursday—1 Are you to be there? L. Jenyns writes me word he wants to get up a discussion about the limitation of species—2 He means to attack the subject thro’ Ornithology. I have a case or two this year among plants— 3

I have clearly reduced Centaurea nigrescens or decipiens (of Bab. 4 ) to C. nigra, after about 4 years culture— I think I told you I have had a small bed of Ægilops squarrosa self sown for the last 3 or 4 years— This year one plant in the very midst of the patch assumed the triticoidal character, which has been noticed in 2 other species—5 I have carefully netted it—& watched it but from its appearance I begin to fear it will not ripen any seed. I had fancied it to be a clear example of Ægilops passing to wheat—& certainly it is a most remarkable plant— It may however be a hybrid between the Ægilops & some revet wheat (?)— It is upright, & the ear has long straight awns & is quite downy. Would you like some seeds of the Ægilops now ripe?6 I have manured a piece of the border next the patch, & mean to extend my experiment next year over it— You have not told me yet what seeds you would like us to get for you— We have been in a greater

CD annotations

crossed pencil
following‘[’added pencil; crossed pencil
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Top of first page: ‘(3)’7 brown crayon


The British Association for the Advancement of Science meeting was held at Cheltenham, 6–13 August 1856. CD did not attend.
Leonard Jenyns read a paper at the British Association meeting entitled ‘On the variation of species’ (Jenyns 1856).
Described in Henslow 1856, a paper delivered at the British Association meeting in Cheltenham. See also letter from J. D. Hooker, 10 July 1856.
CD had sown seeds from the second generation of Henslow’s experimental Aegilops in the spring of 1856 (see letter to J. S. Henslow, 6 August [1856] and n. 3).
Scraps marked ‘3’ frequently concern cross- and self-fertilisation and the number may have referred to chapter 3 of Natural selection, ‘On the possibility of all organic beings crossing’.


Henslow, John Stevens. 1856. On the triticoidal forms of Ægilops and on the specific identity of Centaurea nigra and C. nigrescens. Report of the 26th meeting of the British Association for the Advancement of Science held at Cheltenham, Transactions of the sections, pp. 87–8.

Jenyns, Leonard. 1856. On the variation of species. Report of the 26th meeting of the British Association for the Advancement of Science held at Cheltenham, Transactions of the sections, pp. 101–5. [vols. 6,7,8]

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.


One plant in self-sown patch of Aegilops has assumed a triticoidal character; JSH feels it may be an example of Aegilops passing to wheat.

Letter details

Letter no.
John Stevens Henslow
Charles Robert Darwin
Sent from
Source of text
DAR 166: 178
Physical description
inc †

Please cite as

Darwin Correspondence Project, “Letter no. 1936,” accessed on 24 April 2024,

Also published in The Correspondence of Charles Darwin, vol. 6