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Darwin Correspondence Project

To Roland Trimen   31 January [1863]1

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

Jan. 31st

My dear Sir

I thank you most sincerely for your pleasant letter & M.S. on Orchids. Your sketches seem to me very good, & wonderful under circumstances of their execution.2 I cannot say how much interested I have been in studying your descriptions. I think I understand all; but these orchids (except Eulophia) are so surprisingly different from anything that I have seen that I could hardly make them out for some time & even fancied in some cases that you had miscalled upper sepal & Labellum. But at last I see my way. I am no more a Botanist than you say you are, and I know nothing of any orchids except those seen by me. Therefore I was astonished at the upper sepal being produced into a nectary;3 even more astonished at stigma standing high above the pollinia &c &c.— How curious the pollinium of Disperis!—4 What beautiful and new contrivances you show, & how well you have studied them! Upon the whole I think No V. & VI unnamed (I have sent your drawings to Prof. Harvey to name for me) have interested me most:5 everything seems to occur in a reversed direction compared with our true Orchis.— You do not mention any movement of the pollinia, when attached to an object; & as you are so acute an observer, I infer that there are no such movements;6 & indeed in those you describe such movements would be superfluous. If you have time to wander about do watch some kinds & see insects do the work. Those with long nectaries would be probably hopeless to watch as probably fertilised by Moths.—7 But since my publication I have ascertained that with Orchis, Diptera are chief workmen.—8 They certainly do puncture the walls of nectary, & so get juice. Disperis would be grand to watch. & discover what attracts insects— You draw so well, & have so seized on the subject that you ought really to take up 2 or 3 of the most distinct genera, & watch them, experiment on them by mutilation of parts, & describe them & send over an excellent paper to Linnean Socy or some other Socy.—9 I have so much other work, that I hardly know whether I shall ever publish again,—not but what I have already collected some curious new matter; for the subject delights me—& I cannot resist observing.10

I am very glad to hear that you do not now think me so dangerous a person!11 You will gradually, I can see, become as depraved, as I am.— I believe, or am inclined to believe, in one or very few primordial forms, from community of structure & early embryonic resemblances in each great class..—

With most cordial thanks I remain my dear Sir | Yours sincerely | Ch. Darwin

P.S. Would it be asking too great a favour to beg you to put 2 or 3 flowers of Satyrium or your No V. or VI in bottle with spirits & water, & send home by any opportunity. I would then compare your drawings & add some remarks on your authority, if I ever publish again— But I hope, what will be much better, to see a paper by yourself.—

If you come across Bonatea pray study it— it seems most extraordinary in description.—12


The year is established by the reference to Trimen 1863 (see n. 2, below).
Trimen’s letter, the manuscript of his observations on South African orchids, and the accompanying sketches have not been found. CD later reworked some of Trimen’s observations as a paper for the Linnean Society, noting that it was ‘drawn up from Notes and Drawings sent to C. Darwin’ (see Trimen 1863, p. 144); however, the published illustrations were some of those sent with Trimen’s letter to CD of 16 March 1863. See also letter to Roland Trimen, 23 May [1863].
See n. 6, below.
See Orchids 2d ed., p. 265.
CD’s letter to William Henry Harvey and Trimen’s sketches have not been found. However, see the letter from W. H. Harvey, 3 February 1863. Harvey was professor of botany at Trinity College, Dublin; he had collected extensively in the Cape colony between 1836 and 1842 when he was colonial treasurer (DNB).
In Trimen 1863, pp. 146–7, Trimen described pollinia movements in Disa; CD discussed these observations in Orchids 2d ed., p. 77: The superb flowers of Disa grandiflora have been described and figured by Mr. Trimen. The posterior sepal, instead of the labellum, is developed into a large nectary. In order that insects may reach the copiously stored nectar, they must insert their proboscides on either side of the column; and in accordance with this fact the viscid discs are turned outwards in an extraordinary manner. The pollinia are crooked, and when removed bend downwards from their own weight, so that no movement is necessary for placing themselves in a proper position. See also ‘Fertilization of orchids’, p. 144 (Collected papers 2: 141).
In Trimen 1863, p. 147, Trimen suggested that the orchids with long nectaries might also be attractive to ‘some day-flying Hymenopterous or Lepidopterous insect’. CD later published a comment on Trimen’s observation of a ‘Dipterous insect, allied to Bombylius, frequenting the flowers’ (‘Fertilization of orchids’, p. 144; Collected papers 2: 141).
CD refers to Orchids, published in May 1862; he included this point in ‘Fertilization of orchids’, p. 142 (Collected papers 2: 139–40). See also Correspondence vol. 10, letter to Asa Gray, 1 July [1862].
See n. 2, above.
In 1869, CD published additional material on orchids as ‘Fertilization of orchids’ (Collected papers 2: 138–56); this was originally prepared for the French edition of Orchids (Rérolle trans. 1870). The second edition of Orchids, incorporating this and other new material, was published in 1877 (Freeman 1977).
Edward Bagnall Poulton’s anniversary addresses (Poulton 1909) included an account by Trimen describing the first time he met CD; in his letter (now missing, see n. 2, above), Trimen appears to have told CD of a friend’s admonition that CD was ‘the most dangerous man in England’ (see ibid., pp. 213–15).
Trimen published an account of the structure of the flower of Bonatea in Trimen 1864; there is an annotated copy of this paper in the Darwin Pamphlet Collection–CUL.


Thanks RT for his letter and MS.

Is astonished by the different forms of orchids he describes.

Urges RT to describe and experiment with two or three of the more distinct genera.

"I believe, or am inclined to believe in one or very few primordial forms, from community of structure and early embryonic resemblances in each great class."

Letter details

Letter no.
Charles Robert Darwin
Roland Trimen
Sent from
Source of text
Royal Entomological Society of London (Trimen papers, box 21: 54)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3956,” accessed on 16 February 2019,

Also published in The Correspondence of Charles Darwin, vol. 11