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Darwin Correspondence Project

From Richard Trevor Clarke   6 November [1866]1

Dear Mr Darwin

As some good matter appeared in our first number of the new issue of the RHS transactions on the subject of hybridism   I shall have to say my word in the second;2 my object in writing to you is to know if you would mind my publishing my observation on the change of colour in Matthiola seed produced by pollen agency before germination. Having sent it to you to add to your collection of facts I would not publish it now unless entirely agreeable to you—3

Naudin and Vichura’s observations are good & interesting, especially the “loves of the Willows”, highly confirmatory, but new, no.4 I have not a scrap of novelty for you this season,—any more than the Frenchman.

I have been making some splendid cross bred cottons, but I fear the posterity will not come up to the first crosses always vigorous and good vide also Vichura.5

The Oriental Gossypia will not cross with Barbadense.—6

Very truly yrs | R Trevor Clarke

Welton Place

Novr 6th

Sea Island cottons7 are dimorphous occasionally, style sometimes exserted, beyond anthers, sometimes covered; no concomitant phenomena yet observed.


The year is established by the reference to the first number of the new series of the Journal of the Royal Horticultural Society; see n. 2, below.
The Journal of the Royal Horticultural Society n.s. 1 (1866) carried two papers on hybridism, an English translation of Naudin 1864 (pp. 1–9) and an English abstract of Wichura 1865 (pp. 57–82). There was no article by Clarke in volume 2 of the Journal of the Royal Horticultural Society.
CD noted Clarke’s observations of Matthiola in Variation 1: 398–9, citing Clarke’s paper on Matthiola read at the International Horticultural Exhibition, London, in May 1866 (Clarke 1866). No previous correspondence on the subject has been found.
Clarke refers to Charles Victor Naudin and Max Ernst Wichura, and to Naudin 1864 and Wichura 1865. CD’s copy of Naudin 1864 is in the Darwin Pamphlet Collection–CUL; his annotated copy of Wichura 1865 is in the Darwin Library–CUL (see Marginalia 1: 871–3). CD had finished reading Wichura’s paper in early February 1865, noting in a letter to M. E. Wichura, 3 February [1865] (Correspondence vol. 13): ‘the extreme frequency of Hybrid Willows is quite a new fact to me’. CD commented on Naudin’s theory of the reversion of hybrids in the same letter.
Wichura had given instances where hybrid willows were so vigorous that they outnumbered their parent species (Wichura 1865, pp. 64–5; see Correspondence vol. 13, letter to M. E. Wichura, 3 February [1865] and n. 3).
In a published account of a lecture given at the Royal Horticultural Society on the cultivation of cotton, Clarke discussed the variability of the genus Gossypium, noting that it included two main divisions, which he referred to as Asian and American, and mentioned growing the Asian species G. arboreum (see Gardeners’ Chronicle 1864, p. 1086). The cross that Clarke unsuccessfully attempted was probably between G. arboreum and G. barbadense. For more on Clarke’s observations, see Correspondence vol. 12, letter from R. T. Clarke, 25 November [1864].
‘Sea island’ was the name given to a cultivar of Gossypium barbadense grown in a limited coastal region of the south-eastern United States (see C. W. Smith and Cothren eds. 1999, pp. 154–7, 831; see also Correspondence vol. 12, letter from R. T. Clarke, 25 November [1864], n. 3).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

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.

Naudin, Charles Victor. 1864. De l’hybridité considérée comme cause de variabilité dans les végétaux. Comptes rendus hebdomadaires des séances de l’Académie des Sciences 59: 837–45.

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

Wichura, Max Ernst. 1865. Die Bastardbefruchtung im Pflanzenreich erläutert an den Bastarden der Weiden. Breslau: E. Morgenstern.


Wants to publish his observation on colour changes in Matthiola seeds.

Has been crossing cotton.

Approves of C. V. Naudin and Max Wichura.

Letter details

Letter no.
Richard Trevor Clarke
Charles Robert Darwin
Sent from
Source of text
DAR 161: 163
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4932,” accessed on 27 October 2021,

Also published in The Correspondence of Charles Darwin, vol. 14