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Darwin Correspondence Project

To H. G. Bronn1   11 July 1862

Down Bromley Kent

July 11th.

Dear & Honoured Sir

I am very sorry to be troublesome, but I hope you will insert following note to “Mormodes”* p. 265. (7 lines from bottom) instead of the short one before sent.2

I have now examined perfect flowers of this orchid. It is the Cynoches ventricosum.3 I have erred to a certain extent in my conjectures on the action of the parts. The sensitive point lies in some part of the filament of the anther, between two little leaf-like appendages on the summit of the column. The movement of the pollinium is nearly the same as in Mormodes ignea, & the anther is torn off. But the power of ejection is more feeble; & the viscid surface of the disc after the movement projects at right angles to the anther. There can be no doubt that insects either alight on, or touch, the anther or end of the column, which hangs downwards, & then the disc is flirted out, & sticks probably to their heads; but the whole pollinium is not shot to a distance as in Catasetum. In about quarter of an hour the pedicel of the pollinium slowly straightens itself, as in the case of Mormodes ignea.

July 1862

p. 324 (3 lines from bottom) Orchids*

[asterisk]I now find that in several, perhaps in most of the Arethuseæ,—a tribe which as stated I had until lately no opportunity of examining,—the pollen-grains are simple, that is are not compounded of three or four granules.4

July 1862

Dear sir | Yours truly obliged | Ch. Darwin


CD had not yet learned that on 5 July 1862 Bronn had died suddenly of a heart attack (see letter from E. Schweizerbart’sche Verlagsbuchhandlung, 11 July 1862).
Immediately prior to his death, Bronn had been working on the German translation of Orchids (Bronn trans. 1862), and had sent CD a list of queries (see letter from H. G. Bronn, 21 June 1862). In his reply (letter to H. G. Bronn, 30 June [1862]), CD sent a number of corrections and additions to be incorporated into the translation. Despite Bronn’s death, the two notes given here were included in Bronn trans. 1862, pp. 163 n. and 198 n.
CD misspelled ‘Cycnoches’. In Orchids, pp. 265–9, CD had described an unnamed species of Mormodes, sent to him by James Veitch Jr. Veitch subsequently sent CD further flowers from the same plant, which CD described in notes dated 9 July 1862 (DAR 70: 103–4); these notes were headed ‘Cycnoches Ventricosum | named by Lindley’. See also ‘Fertilization of orchids’, p. 155 (Collected papers 2: 151–2).
Before publishing Orchids, CD had been anxious to examine a specimen of the ‘great Division of Arethuseæ’ as described in Lindley 1853 (see Correspondence vol. 9, letter to J. D. Hooker, [28 July – 10 August 1861]), but he reported in Orchids, p. 324, that he had not been able to do so. Since publishing Orchids, he had received specimens and descriptions of several of the genera ascribed to this tribe in Lindley 1853. CD’s notes, dated 30 May 1862, on a specimen of Vanilla sent to him by Joseph Dalton Hooker, describe the pollen as consisting of ‘single grains’ (DAR 70: 94–5). He also received a dried specimen of Arethusa from Asa Gray, the structure of which he considered ‘very like Vanilla’ (letter to Asa Gray, 10–20 June [1862]), and a description from Gray of Pogonia ophioglossoides, CD’s notes on which, dated 23 June [1862], describe the pollen as consisting of a ‘single grain’ (DAR 70: 80).


Sends additional notes.

Letter details

Letter no.
Charles Robert Darwin
Heinrich Georg Bronn
Sent from
Source of text
Houghton Library for Rare Books and Manuscripts, Harvard University (Lowell Autograph)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3652,” accessed on 23 September 2019,

Also published in The Correspondence of Charles Darwin, vol. 10