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Darwin Correspondence Project

To Friedrich Hildebrand   25 June [1864]1

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

June 25

Dear Sir

I am much obliged for your letter & for your great kindness in sending me the Orchids. They closely resemble English specimens & the 2 stigmas still appear to me distinct tho’ so close.2 I will with the greatest pleasure send you any papers I may publish.3 But I am now only slowly recovering my strength after a nine month’s illness & have only just recently begun to write. I have seen no one for very many months & therefore had not heard of the death of Prof. Treviranus4

I have written a paper on Lythrum which when printed will I think interest you.5 When you publish on Pulmonaria officinalis, I hope you will send me a copy or inform me where it is published; for this genus interests me much.6 You will be surprized to hear that I have some long-styled seedlings with no other form & these tho’ protected from insects have produced a very few seeds.7 I have made many experiments on Pulmonaria angustifolia with well-marked, but rather complex, results; but perhaps I shall not publish till my experiments are repeated next year.8

I believe I know to what you refer about Salvia & there is not a more curious contrivance, I think, in the vegetable kingdom; it is well worth describing, not that I intend to do so.9

With sincere thanks & respect believe me Dear Sir | yours very faithfully | Charles Darwin


The year is established by the reference to the letter from Friedrich Hildebrand, 21 June 1864.
See letter from Friedrich Hildebrand, 21 June 1864 and nn. 2 and 3. In his review of Orchids, Hildebrand’s colleague Ludolph Christian Treviranus had claimed that the stigmas of Orchis pyramidalis were joined together, rather than separated as in CD’s diagram (see Orchids, p. 22, and Treviranus 1863c, p. 243; see also ‘Fertilization of orchids’, p. 141 (Collected papers 2: 139), and Orchids 2d ed., p. 24 n.).
Hildebrand’s name is on the presentation lists for ‘Three forms of Lythrum salicaria, Variation, ‘Illegitimate offspring of dimorphic and trimorphic plants’, Cross and self fertilisation, Insectivorous plants, and Movement in plants (see Correspondence vol. 12, Appendix III and DAR 210.11: 23, 28, 29, 33).
See letter from Friedrich Hildebrand, 21 June 1864 and n. 11. Hildebrand’s observations on Pulmonaria officinalis were published in Hildebrand 1865, pp. 13–15. An annotated copy of the paper is in the Darwin Pamphlet Collection–CUL. See also letter to J. D. Hooker, 10 December [1864] and n. 19.
See letter from L. C. Wedgwood, [6 June 1864] and n. 5, and letter from Friedrich Hildebrand, 21 June 1864 and n. 11. Hildebrand’s observations of Pulmonaria officinalis indicated that the long-styled form was self-sterile; however, CD’s observations suggested that the plant was self-fertile. CD continued his observations of P. officinalis for several years, and reported his conclusions in Forms of flowers, pp. 101–4 (see also his notes in DAR 110: A44 v., A55). In ‘Illegitimate offspring of dimorphic and trimorphic plants’, pp. 430–1, CD expressed doubt whether his specimens of P. officinalis were of the same species as those described by Hildebrand.
CD began crossing different forms of Pulmonaria angustifolia in June 1864, and by July had concluded that the long-styled form was self-sterile (see DAR 110: A48, A54, ‘Illegitimate offspring of dimorphic and trimorphic plants’, pp. 430–1, and Forms of flowers, pp. 107–10). For CD’s preliminary investigations of P. angustifolia, see, for example, letter from W. E. Darwin, 14 April [1864] and n. 1, and letter to W. E. Darwin, 14 May [1864].
See letter from Friedrich Hildebrand, 21 June 1864 and n. 9. In Hildebrand 1866, Hildebrand described variable mechanisms in different Salvia species that facilitated pollination; these involved movements of the anthers and sometimes of the pistil caused by insects landing on the flowers; see especially CD’s annotations on pp. 15 and 16 of his heavily annotated copy of Hildebrand 1866 in the Darwin Pamphlet Collection–CUL. CD referred to the ‘admirable mechanical adaptations in this genus for favouring or ensuring cross-fertilisation’ in Cross and self fertilisation, p. 93 n., citing the work of Hildebrand and others. See also letter to Friedrich Hildebrand, 16 May [1866], Calendar no. 5092.


Calendar: A calendar of the correspondence of Charles Darwin, 1821–1882. With supplement. 2d edition. Edited by Frederick Burkhardt et al. Cambridge: Cambridge University Press. 1994.

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

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

Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

‘Fertilization of orchids’: Notes on the fertilization of orchids. By Charles Darwin. Annals and Magazine of Natural History 4th ser. 4 (1869): 141–59. [Collected papers 2: 138–56.]

Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.

‘Illegitimate offspring of dimorphic and trimorphic plants’: On the character and hybrid-like nature of the offspring from the illegitimate unions of dimorphic and trimorphic plants. By Charles Darwin. [Read 20 February 1868.] Journal of the Linnean Society of London (Botany) 10 (1869): 393–437.

Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

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

Orchids 2d ed.: The various contrivances by which orchids are fertilised by insects. By Charles Darwin. 2d edition, revised. London: John Murray. 1877.

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.

‘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.]

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


Thanks for orchids.

Recovering from nine months’ illness.

Discusses fertilisation of Pulmonaria.

Please cite as

Darwin Correspondence Project, “Letter no. 4545,” accessed on 25 February 2021,

Also published in The Correspondence of Charles Darwin, vol. 12