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Darwin Correspondence Project

To J. J. Weir   5 July 1875

Down, Beckenham, Kent [Abinger Hall, Surrey.]

July 5, 1875

My dear Sir

Please to look over the enclosed note and return it to me.1 I am very much interested in the subject, and should be glad to know whether you keep to the same judgment and whether you have made any further observations. Am I right in supposing that none of the flowers were of a hybrid or mingled nature like those of C. Adami? for this makes your case very peculiar? Your letter is dated 1870, and I should like to know whether the grafted C. purpureus produced a twig bearing yellow flowers during this or some previous year.2

I am especially desirous to learn how the tree has behaved since you wrote to me.

I am correcting a new edit. of my Var., and I feel sure that you will excuse my troubling you.3

Yours very sincerely | Ch. Darwin.


CD evidently enclosed the letter from J. J. Weir, 27 June 1870 (Correspondence vol. 18).
Weir had described specimens of the yellow-flowered Cytisus alpinus (now Laburnum alpinum, Scotch laburnum) that were grafted with the purple broom, C. purpureus, resulting in branches with either yellow or purple flowers, but no intermediate forms (Correspondence vol. 18, letter from J. J. Weir, 27 June 1870). In Variation 1: 390 n. 94, CD had described a hybrid ‘C. alpino-laburnum’ with characteristics exactly intermediate between the parent forms. Cytisus adami is a graft hybrid of the common yellow laburnum, C. laburnum (now Laburnum anagyroides), and C. purpureus; C. adami is now known as +Laburnocytisus adamii (Bean 1970–88, 2: 510–11). CD discussed C. adami in Variation 1: 387–90, noting that some branches bore the dingy red flowers of the hybrid form, while others commonly reverted to the parent species, bearing either yellow or purple flowers, or flowers that were half yellow and half purple.
CD began work on Variation 2d ed. on 6 July 1875 (CD’s ‘Journal’ (Appendix II)). For the discussion of Cytisus adami, see Variation 2d ed. 1: 413–17.


Bean, William Jackson. 1970–88. Trees and shrubs hardy in the British Isles. 8th edition, fully revised by D. L. Clarke and George Taylor. 4 vols. and supplement. London: John Murray.

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

Variation 2d ed.: The variation of animals and plants under domestication. By Charles Darwin. 2d edition. 2 vols. London: John Murray. 1875.

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


Discusses case of Cytisus graft described by JJW.

Letter details

Letter no.
Charles Robert Darwin
John Jenner Weir
Sent from
Source of text
DAR 148: 334
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10043,” accessed on 25 September 2020,

Also published in The Correspondence of Charles Darwin, vol. 23