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Darwin Correspondence Project

From W. T. Thiselton-Dyer   10 June 1879

Royal Gardens Kew

June 10. 79

Dear Mr Darwin

We are looking up plants for you and I will write again about them.1

When you were interested in sleep did you examine Crotalaria. It is a monophyllous Leguminous plant which turns its leaves up against the stem.2 The under side of the leaves is covered with bloom and the aspect of the sleeping plants is singular—something like this.


I also venture to send you a note extracted from the Gardeners’ Chronicle about the meal on Auriculas which strikes me as curious but which doubtless you know all about.3

We all went last night to hear Mr Ball at the Geographical Society on the Alpine Flora.4 The gist of his story was that the Alpine Flora is the direct and continuous descendant of that which existed on the Palæozoic alps when the vallies were filled with an atmosphere too highly charged with Carbonic acid to allow of any thing

CD annotations

2.1 When … Crotalaria.] scored red crayon; ‘What Tribe’ red crayon ‘Tribe II Genisteae comes before Lupinus’ ink ‘Put after Lupinus’5 pencil
4.2 The … thing 4.6] scored red crayon; ‘Yes Like Sir W. Thomson’6 red crayon
End of letter: ‘I agree to all your many criticisms— It is a pity— it is enough to make GD7 a laughing stock [to]blue crayon


Crotalaria is the genus of rattlebox.
The note, reporting a preliminary chemical analysis of the meal suggesting it was probably an alkaloid, was in a printed extract from Gardeners’ Chronicle, 31 May 1879, p. 700, and is in DAR 68: 5. The leaves and flowers of many varieties of auricula (Primula auricula) and other species of Primula have a coating of meal or farina produced by glandular hairs that secrete an opaque waxy substance composed primarily of flavones.
John Ball’s paper ‘On the origin of the flora of the European Alps’ was published in Proceedings of the Royal Geographical Society and Monthly Record of Geography (Ball 1879).
In Genera plantarum (Bentham and Hooker 1862–83, 1: 434–600), the natural order Leguminosae was divided into suborders and tribes. Genisteae was tribe II of the suborder Papilionaceae (ibid., p. 439–42). In CD’s list of plants that sleep, Crotalaria appears before Lupinus under the heading ‘Leguminosae Tribe II’ (Movement in plants, p. 320). Lupinus is the genus of lupine.
CD’s annotation is a note for his reply (see letter to W. T. Thiselton-Dyer, 18 June 1879 and n. 5). William Thomson’s calculations of the age of the earth, based on estimates of heat loss, were at odds with those of geologists, based on estimates of gradual erosion and deposition; Thomson had criticised CD’s estimate in Origin, pp. 285–7, of 300 million years for the denudation of the Weald (see W. Thomson 1862, pp. 391–2).
GD: geographical distribution.


Ball, John. 1879. On the origin of the flora of the European Alps. [Read 9 June 1879.] Proceedings of the Royal Geographical Society and Monthly Record of Geography 1: 564–89.

Bentham, George and Hooker, Joseph Dalton. 1862–83. Genera plantarum. Ad exemplaria imprimis in herbariis Kewensibus servata definita. 3 vols. in 7. London: A. Black [and others].

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

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Thomson, William. 1862a. On the age of the sun’s heat. Macmillan’s Magazine 5: 388–93.


Sleep in Crotalaria.

Report of John Ball’s lecture to Geographical Society: Alpine flora is direct descendant of Palaeozoic flora ["On the origin of the flora of the European Alps", Proceedings of the Royal Geographical Society and Monthly Record of Geography 1: 564–88].

Letter details

Letter no.
William Turner Thiselton-Dyer
Charles Robert Darwin
Sent from
Source of text
DAR 209.10: 85
Physical description
AL 4pp † inc

Please cite as

Darwin Correspondence Project, “Letter no. 12099,” accessed on 7 June 2023,