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

LS(A)

1
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.
2
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.
3
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).
4
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.

Manuscript Alterations and Comments

Please cite as “DCP-LETT-11139,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11139