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Darwin Correspondence Project

To R. I. Lynch   14 September 1877

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

Sep 14. 1877

Dear Sir,

I am much obliged for your notes.1 By an odd coincidence I saw last night the cotyledons of Cassia fast asleep, & this morning ascertained that they moved after being touched.2 I am interested about the Euphorbia; will you be so good as to shake the shoot for a couple of minutes, or what is perhaps better tap one of the young leaves with a delicate twig, first on the upper surface & then below; & observe whether it afterwards moves at all.3 Should this be the case & if the plant could be spared I should very much like to experimentize on it: & you could then show this note to Mr Dyer4

Dear Sir | yours faithfully | Ch. Darwin


See letter from R. I. Lynch, [before 14 September 1877]; see also letter to R. I. Lynch, 23 August [1877], and letter from R. I. Lynch, [28 August 1877]. Lynch, foreman of the propagating department at Kew Gardens, had been observing plants that slept on CD’s behalf.
CD’s notes on his observations of Cassia calliantha (a synonym of Senna multijuga subsp. multijuga), recorded at intervals throughout the day on 14 September [1877], are in DAR 209.1: 22; he continued to trace the movement of the terminal leaflets over the next few days (DAR 209.1: 23r). There are further observations from later in September in DAR 209.4: 99–107.
See letter from R. I. Lynch, [before 14 September 1877]. Earlier in the year, Joseph Dalton Hooker had suggested Euphorbia (spurge) as a plant that might interest CD, but for his investigation of bloom on leaves of plants rather than their capacity to sleep (letter from J. D. Hooker, 31 May 1877).
William Turner Thiselton-Dyer was assistant director at the Royal Botanic Gardens, Kew. According to the Kew Outwards book, a specimen of Euphorbia jacquiniiflora (a synonym of E. fulgens, the scarlet plume) was sent to CD on 18 September 1877; his experimental notes are in DAR 209.14: 22–3.


Thanks RIL for notes.

Asks about movement of Euphorbia.

Letter details

Letter no.
Charles Robert Darwin
Richard Irwin Lynch
Sent from
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description
LS(A) 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 11139,” accessed on 28 February 2024,