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Darwin Correspondence Project

To Alphonse de Candolle   4 August [1863]

Down. | Bromley. | Kent. S.E.

Aug. 4th

My dear Sir

Will you permit me to beg you to interest any young Botanist at Geneva to observe one point for me. But the possibility rests on Lythrum Thymifolia or Hyssipifolia growing near you & being still in flower. Vaucher says (Hist. Phys. Tom. 2. p. 371)1 that these two species are dimorphic like Primula. I have examined several dried specimens of L. hyssipifolia & can see no trace of this fact.2 If either species present any difference in length of pistil & stamens, it is most likely that three forms should be presented. Could you get this point looked at for me; & if possible a few flowers of the two or three forms sent me in a letter.3 I may add that in some species of Lythrum two of the forms have the pistil hidden within the calyx.

I have been trying most laborious experiments on L. salicaria, & am extremely anxious to hear about & see if possible, L. thymifolia.—4

I trust to your kindness to forgive me for troubling you & remain, my dear Sir, with sincere respect | Yours very faithfully | Ch. Darwin


Vaucher 1841, 2: 371. There is an annotated copy in the Darwin Library–CUL (see Marginalia 1: 812–5). For CD’s interest in Lythrum, see letter from John Scott, [26 July – 2 August 1863] and n. 6.
CD’s observational notes on L. hyssopifolia are in DAR 27: B41a–44 and DAR 109: B92. CD evidently thought that L. hyssopifolia growing wild in Switzerland might differ from the specimens he had examined.
Candolle’s reply has not been found.
See letter from John Scott, [26 July – 2 August 1863] and n. 6. Lythrum salicaria, L. thymifolia, and L. hyssopifolia are discussed in ‘Three forms of Lythrum salicaria. CD concluded that L. thymifolia was non-dimorphic; Candolle was not cited (‘Three forms of Lythrum salicaria, p. 191 (Collected papers 2: 124)).


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

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.

‘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.]

Vaucher, Jean Pierre Etienne. 1841. Histoire physiologique des plantes d’Europe ou exposition des phénomènes qu’elles présentent dans les diverses périodes de leur développement. 4 vols. Paris: Marc Aurel Frères.


Asks AdeC to observe two species of Lythrum to see whether they are dimorphic as stated by Vaucher. CD can find no trace of this in dried specimens he has examined; "if either species present any difference in length of pistil and stamens, it is most likely that three forms should be presented".

Letter details

Letter no.
Charles Robert Darwin
Alphonse de Candolle
Sent from
Source of text
Archives de la famille de Candolle (private collection)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4263,” accessed on 23 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 11