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To W. T. Thiselton-Dyer   22 July [1877]1

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

July 22nd

My dear Dyer

Many thanks for seeds of the Malva & information about Averrhoa, which I perceived was sensitive as A. carambola is said to be; & about Mimosa sensitiva.—2

The Log-wood has interested me much:3 the wax is very easily removed especially from the older leaves, & I found after squirting on the leaves with water at 95°, all the older leaves became coated after 48 hours in an astonishing manner with a black Uredo, so that they looked as if sprinkled with soot & water. But not one of younger leaves was affected. This has set me to work to see whether the “bloom” is not a protection against parasites.

As soon as I have ascertained a little more about this case (& generally I am quite wrong at first) I will ask whether I could have a very small plant, which shd. never be syringed with water above 60°, & then I suspect the leaves wd. not be spotted, as were the older ones on the plant when it arrived from Kew, but nothing like what they were after my squirting.

In an old note of yours, (which I have just found) you say that you have a sensitive Schrankia: could this be lent me?4 I have had lent me a grey Coral-tree (Erythrina) which is very sickly, yet shows odd sleep movements: I suppose I cd. buy one, but Hooker told me first to ask you for anything.5

Lastly: have you any sea-side plants with bloom? I find that drops of sea-water corrode sea-kale if bloom is removed; also the var. littorum of Triticum repens6 (By the way my plants of the latter grown in pots here are now throwing up long flexible green blades, & it is very odd to see on the same culm, the rigid, grey, bloom-covered blades & the green, flexible ones)

Cabbages, ill-luck to them, do not seem to be hurt by salt-water. Hooker formerly told me that Salsola Kali, a var. of Salicornia—1 sp. of Suæda—Euphorbia peplis—Lathyrus maritimus—Eryngium maritimum—were all glaucous & sea-side plants.7 It is very improbable that you have any of them or of foreigners with the same attributes.—

God forgive me: I hope that I have not bored you greatly | Yours very sincerely | Ch. Darwin

By all the rules of right the leaves of the Logwood ought to move (as if partially going to sleep) when syringed with tepid water: the leaves of my little plant do not move at all, & it occurs to me as possible, though very improbable, that it wd. be different with a larger plant with perhaps larger leaves: would you some day get a gardener to syringe violently with water kept in hot-house a branch on one of your largest Log-wood plants & observe whether leaves move together towards the apex of leaf.—

The largest leaf on my plant is only 2$\frac{1}{4}$ inches in extreme length.

Frank has made a beautiful observation on Drosera, viz that the leaves fed with meat include incomparably more starch-granules than the unfed leaves.—8

By the way what astonishing nonsense Mr. Andrew Murray has been writing in Gardener’s Chronicle about leaves & carbonic acid.9 I like to see a man behaving consistently like a fool.—

What a lot I have scribbled to you!

Footnotes

The year is established by the relationship between this letter and the letter from W. T. Thiselton-Dyer, 16 July 1877.
See letters from W. T. Thiselton-Dyer, 16 July 1877 and 18 July [1877]. Thiselton-Dyer had sent to Paris for seeds of Malva peruviana (a synonym of Fuertesimalva peruviana). He had also sent CD a plant of Averrhoa bilimbi instead of Averrhoa carambola, which they did not have at Kew.
See letter from W. T. Thiselton-Dyer, 16 July 1877. Logwood: Haematoxylum campechianum.
Joseph Dalton Hooker. CD discussed Erythrina corallodendron in Movement in plants, p. 367.
Seakale: Crambe maritima. Triticum repens is a synonym of Elymus repens (couch grass). Var. littorum: seaside variety (Latin).
Salsola kali: prickly Russian thistle. Salicornia: glasswort. Suaeda: seepweed. Euphorbia peplus: petty spurge. Lathyrus maritimus is a synonym of L. japonicus var. maritimus (beach pea). Eryngium maritimum is sea holly.
See F. Darwin 1878a, p. 23. Francis Darwin was experimenting on Drosera rotundifolia (common or round-leaved sundew), to prove CD’s theory in Insectivorous plants that the plants derived signficant advantage from a carnivorous diet.
See A. Murray 1877. Murray denied that plants derived carbon dioxide from the the atmosphere.

Bibliography

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.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Murray, Andrew. 1877. Experiments on the flow of the sap. Gardeners’ Chroncle, 21 July 1877, pp. 72–4.

Summary

Describes experiments on sensitivity of plant leaves to water.

Frank [Darwin] has found that Drosera leaves fed with meat contain more starch.

Letter details

Letter no.
DCP-LETT-11066
From
Charles Robert Darwin
To
William Turner Thiselton-Dyer
Sent from
Down
Source of text
Royal Botanic Gardens, Kew (Darwin: Letters to Thiselton-Dyer, 1873–81: ff. 74–7)
Physical description
ALS 7pp

Please cite as

Darwin Correspondence Project, “Letter no. 11066,” accessed on 21 March 2023, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-11066.xml

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