To Francis Darwin   [4 February – 8 March 1879]1

According to Pfeffer’s brief description the leaves of Phyllanthus niruri (one of the Euphorbiaceæ) sleep closely like those of Cassia.—2 I shd. much like to know whether this is really the case. Will you enquire whether by any chance they have this plant (an East Indian annual) or seeds of it   I also want seeds of Medicago maculata—3 It is just possible they may possess such seeds & I am sure Dr Durando, (to whom give my kind remembrances) wd try & get them.4

C. D.

1
The date is established by the reference to Gaetano Durando, a botanist in Algiers. Francis left for Algiers on 4 February 1879 (Emma Darwin’s diary (DAR 242)) and departed from Algiers on 8 March (letter from G. H. Darwin, 3 March 1879). See also letter from Francis Darwin, [c. 25 February 1879].
2
Wilhelm Pfeffer discussed Phyllanthus niruri (gale of the wind) in Die periodische Bewegungen der Blattorgane (The periodic movements of foliage organs; Pfeffer 1875, pp. 159–60). See also Movement in plants, pp. 388–9. On the sleep movements of many species of Cassia, see Movement in plants, pp. 369–73. In these species, and in Phyllanthus niruri, the leaves drop and twist at night so that the lower (abaxial) surfaces turn outwards.
3
CD mentioned a report of the sleep movements of Medicago maculata (a synonym of M. arabica, spotted medick) in Movement in plants, p. 345; according to the report, the leaves rose up and twisted so that the lower (abaxial) face turned skywards.
4
In Cross and self fertilisation, p. 105, CD mentioned that he had received seed from Durando in Algiers; see also Correspondence vol. 18, letters to J. D. Hooker, [29 June 1870] and 10 July 1870. Durando had visited Down in 1878 (letter from Emma Darwin to W. E. Darwin, 17 September [1878] (DAR 219.1: 115)). No reply to this letter has been found, but CD asked William Turner Thiselton-Dyer for specimens and seeds of Phyllanthus niruri and Medicago maculata from Kew in his letter of 24 March 1879.

Please cite as “DCP-LETT-11815,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11815