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Darwin Correspondence Project

To John Traherne Moggridge   19 June [1864]1

Down Bromley

June 19

Dear Sir

I am much obliged for your most interesting letter with the beautiful drawings.2 I have never received any account with so many new facts in so small a compass.

I should be very much obliged if you would inform me whether the cells into which you saw the bee insert its proboscis (in the labellum of O. longibractiata) were closed or open.3 I ask because I now know positively that bees do perforate the labellum of various orchids.4

Have you a dried specimen? for by soaking and cutting off a slice one could see. The convergence of the pollinia is quite a new and interesting fact.5

I have been almost more interested by what you say on the variability of the falling out of the pollen-masses in Ophrys scollopax than on any other point.6 Unless you can shew that the Cannes specimens resemble O. apifera in some characters I think your theory of crossing is rather too bold.7 I have shown though less clearly than you the movements of the pollinia of the Bee Ophrys.8 The seat of motion is never in the caudicle. Shall I return your beautiful drawings? Perhaps you intend to draw up for some Journal or for the Linn. Soc. a brief account of the new points which you have observed. I hope you will do so.9 I have much new matter on Orchids, but my health is so weak and I have so many other subjects on hand that I cannot at all tell when or ever I shall publish again.10

With sincere thanks for your excellent and most interesting letter, I remain, | Dear Sir, | Your’s very faithfully | Charles Darwin

Footnotes

The year is established by the fact that the information referred to subsequently appeared in Moggridge 1864 (see n. 9, below).
Moggridge’s letter has not been found; however, the pencil and watercolour drawings are in DAR 70: 85–8, and are reproduced in the plates between pages 248 and 249. See also plate 16 of Moggridge 1864.
In his 1864 paper, Moggridge stated that he had observed Orchis longibracteata visited by a bee, Xylocopa violacea, which departed from the flower with pollinia attached to its forehead. He also reported seeing the plant visited by one dipterous insect, whose ‘proboscis was dipped into each of the open cells of honeycomb texture, and instantly withdrawn’ (Moggridge 1864, pp. 256–7). Among the drawings enclosed in his letter to CD was a sketch of the bee, together with a sketch of O. longibracteata (see fig. IV on plate facing p. 249). CD reported Moggridge’s observation that the orchid was pollinated by X. violacea in ‘Fertilization of orchids’, p. 143 (Collected papers 2: 140), and Orchids 2d ed., p. 27.
With his letter of 21 January 1864, Hermann Crüger sent CD a manuscript in which he reported that pollinia became attached to the backs of bees while they gnawed the labellum of Catasetum tridentatum. CD communicated the paper (Crüger 1864) to the Linnean Society, where it was read on 3 March 1864 (see letter to Daniel Oliver, 17 February [1864], and letter from Daniel Oliver, 18 February 1864 and n. 1). In Orchids, pp. 282–5, CD had speculated that the excrescences of the labellum in certain orchids could attract feeding insects and thereby facilitate pollination. In ‘Fertilization of orchids’, p. 154 (Collected papers 2: 151), CD reported that his speculations in Orchids had been fully confirmed by Crüger’s findings. CD also noted Crüger’s observations in Origin 4th ed., pp. 230–1, and Orchids 2d ed., p. 270.
See fig. III on plate facing p. 249, and Moggridge 1864, p. 256. CD had described how the movements of pollinia in orchids enabled pollination by insects (see, for example, Orchids, pp. 16–19, 335–9). Moggridge’s observation of the convergence of pollinia in Orchis longibracteata is reported in ‘Fertilization of orchids’, p. 143 (Collected papers 2: 140), and Orchids 2d ed., pp. 26–7.
See fig. I on plate facing p. 248. In his paper, Moggridge reported that Ophrys scolopax appeared in two forms: one found at Cannes that was self-fertile, and another found at Mentone that showed no such tendency. Moggridge maintained that self-pollination was achieved in the case of the Cannes orchid by a ‘slight bend in the anther-cells’ (Moggridge 1864, p. 258). CD cited Moggridge’s account of O. scolopax in ‘Fertilization of orchids’, p. 145 (Collected papers 2: 142), and Orchids 2d ed., pp. 52 and 292–3.
Moggridge did not present his theory in the 1864 paper; however, in his Contributions to the flora of Mentone (Moggridge 1865–8, pls. XIX, XLIII–XLV), he argued that Ophrys scolopax, O. arachnites, O. aranifera, and O. apifera were all varieties of a single species, O. insectifera. In ‘Fertilization of orchids’, p. 145 (Collected papers 2: 142), CD noted Moggridge’s theory, adding that in England the forms did not appear to be varieties of a single species; however, see also Orchids 2d ed., pp. 58–9.
The bee ophrys, Ophrys apifera, is described in Orchids, pp. 63–72. The caudicles are described as flexible and elastic, so that they are set vibrating and the pollen-masses are brought into contact with the stigma by the movement of air (ibid. p. 64–5). The description of O. apifera does not appear in Moggridge 1864 or in Moggridge 1865–8.
Moggridge’s paper ‘Observations on some orchids of the south of France’ (Moggridge 1864) was read to the Linnean Society on 3 November 1864. In the first paragraph, he wrote that his work was based on CD’s Orchids, which had opened for him ‘a fresh and most delightful source of occupation’ (Moggridge 1864, p. 256).
CD published his new material in ‘Fertilization of orchids’ (Collected papers 2: 138–56), and in Orchids 2d ed.

Bibliography

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

Crüger, Hermann. 1864. A few notes on the fecundation of orchids and their morphology. [Read 3 March 1864.] Journal of the Linnean Society (Botany) 8 (1865): 127–35.

‘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.]

Moggridge, John Traherne. 1864. Observations on some orchids of the south of France. [Read 3 November 1864.] Journal of the Linnean Society (Botany) 8 (1865): 256–8.

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.

Origin 4th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 4th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1866.

Summary

Discusses fertilisation of flowers by bees. Thanks JTM for drawings.

Letter details

Letter no.
DCP-LETT-4540
From
Charles Robert Darwin
To
John Traherne Moggridge
Sent from
Down
Source of text
DAR 146: 372
Physical description
2pp

Please cite as

Darwin Correspondence Project, “Letter no. 4540,” accessed on 16 October 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-4540.xml

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

letter