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Darwin Correspondence Project

To J. D. Hooker   27 [October 1862]

Down Bromley Kent


My dear Hooker

I am sorry to hear about Miss Henslow, & not a very good account of Mrs Hooker.1 Our Henrietta has been failing a little in the old way again (do not allude to it) & some of the others are yet very delicate.2 It is a heavy burthen to bear; but I will scribble a bit to you about plants, & forget things. The plants all arrived quite safe.3 Masdevallia turns out nothing wonderful; I was merely stupid about it; I am not the less obliged for its loan, for if I had lived till 100 years old, I shd. have been uneasy about it.4 It shall be returned the first day I send to Bromley.

I have steamed the other plants, & made the Sensitive plant very sensitive, & shall soon try some experiment on it.5 But after all it will only be amusement. Nevertheless, if not causing too much trouble, I shd. be very glad of a few young plants of this & Hedysarum in summer; for this kind of work takes no time & amuses me much.— Have you seeds of Oxalis sensitiva, which I see mentioned in Books.6 By the way what a fault it is in Henslow’s Botany that he gives hardly any references: he alludes to great series of experiments on absorption of poisons by roots, but where to find them I cannot guess.7 Possibly the all knowing Oliver may know.—8 I can plainly see that glands of Drosera from rapid power, almost instantaneous, of absorption & power of movement, give enormous advantage for such experiments. And someday I will enjoy myself with a good set to work; but it will be great advantage if I can get some preliminary notion on other sensitive plants, & on roots.—9

Oliver said he would speak about some seed of Lythrum hyssopifolium being preserved for me.—10 By the way I am rather disgusted to find I cannot publish this year on Lythrum salicaria: I must make 126 additional crosses!!11 All that I expected is true, but I have plain indications of much higher complexity. There are 3 pistils of different structure & functional power & 3 kinds of pollen of different structure & functional power, & I strongly suspect altogether five kinds of pollen, all different in this one species!12

By any chance have you at Kew, any odd varieties of the common Potato: I want to grow a few plants of every var. to compare flowers, leaves fruit &c, as I have done with Peas &c.—13

I am crawling on with my book on variation; but I have had some bad attacks lately. I fear I cannot come to Kew; yet I wish it much to look at specimen (if such you have) of wheat & maize &c; & I shd. enjoy it so much.—14

Farewell. C. Darwin


Throughout 1860 and 1861, Henrietta Emma Darwin had been ill with a fever diagnosed as a form of typhus (see Correspondence vols. 8 and 9). On 13 October 1862, Emma Darwin recorded in her diary (DAR 242): ‘Etty poorly & weak’, and on 24 October: ‘Henrietta languid in m[ornin]g as before’. Horace Darwin had been seriously ill earlier in the year, and Emma and Leonard had been ill with scarlet fever during the summer (see ‘Journal’ (Correspondence vol. 10, Appendix II)). On 13 October, Emma recorded in her diary: ‘all children poorly’, and on 25 October she recorded that she herself was ‘feverish’ with a ‘bad cold’.
CD had been anxious to see again the orchid species Masdevallia fenestrata (a synonym of Zootrophion atropurpureum), since he had previously been unable to explain how fertilisation was effected in this species (see letter from J. D. Hooker, [18 October 1862] and n. 3). His notes, dated 24 October 1862, on the specimen sent from the Royal Botanic Gardens, Kew, are in DAR 70: 105–6. CD published his observations on this specimen in Orchids 2d ed., pp. 135–7, but reiterated his earlier statement that he had failed to understand ‘how insects perform the act of fertilisation’.
See letter from J. D. Hooker, 25 October 1862 and n. 2. CD’s notes, dated 27 October – 5 November 1862, on his experiments with the sensitive plant, Mimosa pudica, are in DAR 209.2: 86; CD exposed the plant to ether and chloroform and observed the effects on the depression of the petiole. These notes also contain a reference to the other plant sent by Hooker, the telegraph plant (Hedysarum gyrans or Desmodium gyrans), which states: ‘I see Hedysarum gyrans drops its leaves downwards at night.’ In his copy of Henslow 1837, pp. 165–6, CD noted with regard to M. pudica: ‘try this with Ether’, and with regard to D. gyrans: ‘Does Desmodium gyrans sleep’; CD’s copy of the work is in the Darwin Library–CUL (see Marginalia 1: 369–71).
From 17 to 20 October 1862, CD carried out experiments on the effects of ether, chloroform, and morphine in modifying the responsiveness of Oxalis acetosella (see the experimental notes in DAR 54: 65 and DAR 60.1: 1); he may have intended to extend the experiments to O. sensitiva (a synonym of Biophytum sensitivum).
In Henslow 1837, pp. 168–9, John Stevens Henslow discussed what he called the ‘Sensibility’ of plants, noting: When corrosive poisons are imbibed into their system, they destroy the tissue much in the same way as in the animal frame; but when narcotic poisons are imbibed, although they kill the plants, they do not appear to have produced any derangement or disorganisation in their tissue. But it has been argued that, as these latter poisons act upon the nervous system of animals, we may suspect something analogous to this system to exist in vegetables also. Henslow went on to note that ‘A long list has been given of substances which act as poisons on plants’. This passage is marked with a marginal line in the annotated copy of Henslow 1837 in the Darwin Library–CUL (see Marginalia 1: 369–71). CD had recently come to the conclusion that some plants ‘must have diffused matter … closely analogous to the nervous matter of animals’ (see letter to J. D. Hooker, 26 September [1862]).
Daniel Oliver was the librarian at the Royal Botanic Gardens, Kew, and one of the compilers of the annual botanical bibliography in the Natural History Review; CD had repeatedly commented on Oliver’s extensive bibliographic knowledge (see letters to J. D. Hooker, 11 June [1862] and 6 October [1862]).
CD did not again work extensively on Drosera rotundifolia until 1872 (LL 3: 322); his experiments on the species consituted the main body of Insectivorous plants, which was published in 1875. CD used species of Mimosa, Desmodium, and Oxalis (see nn. 5 and 6, above) in a further study, published in 1880 as Movement in plants.
CD had carried out ninety-four crosses with Lythrum salicaria in the summer of 1862; however, he decided to carry out further crosses in 1863 in order to be sure of his results (see ‘Three forms of Lythrum salicaria, p. 179 (Collected papers 2: 114), letter to Asa Gray, 9 August [1862], and letter to W. E. Darwin, [25 October 1862]). CD’s paper, ‘Three forms of Lythrum salicaria, was read before the Linnean Society of London on 16 June 1864.
In terms of structure, there are only three kinds of stamen in the different forms of flower of Lythrum salicaria; however, in ‘Three forms of Lythrum salicaria, p. 188 (Collected papers 2: 122), CD observed that the pollen produced by the long and short stamens of the mid-styled form was less potent than the pollen produced by the structurally identical stamens of the other two forms. Thus, functionally speaking, there were, he claimed, five kinds of pollen in this species (‘Three forms of Lythrum salicaria, p. 169; Collected papers, p. 106).
CD was preparing the section of Variation dealing with ‘Facts of variation of Plants’ (see ‘Journal’ (Correspondence vol. 10, Appendix II)); he discussed the variation and cultivation of the potato in Variation 1: 330–1. In the summer of 1855, CD grew in his garden forty-six varieties of pea, and varieties of many other vegetables (see Correspondence vol. 5; see also the experimental notes in DAR 46.2: 3–31, 37–41). CD discussed pea varieties and his own observations on them in Variation 1: 326–30.
Cultivated and wild varieties of wheat and other cereals are discussed in Variation 1: 312–20; varieties of maize are discussed in Variation 1: 320–2. CD did not visit the Royal Botanic Gardens, Kew, until 11 February 1863 (Emma Darwin’s diary (DAR 242)).


Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

LL: The life and letters of Charles Darwin, including an autobiographical chapter. Edited by Francis Darwin. 3 vols. London: John Murray. 1887–8.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.

Orchids 2d ed.: The various contrivances by which orchids are fertilised by insects. By Charles Darwin. 2d edition, revised. London: John Murray. 1877.

‘Three forms of Lythrum salicaria’: On the sexual relations of the three forms of Lythrum salicaria. By Charles Darwin. [Read 16 June 1864.] Journal of the Linnean Society (Botany) 8 (1865): 169–96. [Collected papers 2: 106–31.]

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Masdevallia turns out to be nothing wonderful, "I was merely stupid about it."

Asks for plants for experiments.

Hedysarum and Oxalis sensitiva seeds.

Asks whether Oliver knows of experiments on absorption of poisons by roots.

CD finds he cannot publish this year on Lythrum salicaria; he must make 126 additional crosses!

Asks for odd variations of common potato; he wants to grow a few plants of every variety.

Variation is crawling.

Has had some bad attacks lately.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 115: 167
Physical description
ALS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 3784,” accessed on 22 April 2024,

Also published in The Correspondence of Charles Darwin, vol. 10