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Darwin Correspondence Project

To Roland Trimen   23 May [1863]1

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

May 23d

My dear Sir

I have delayed thanking you for your note & photograph, as I had no photograph by me of myself.2 I have never had a proper “carte” taken; but I enclose a photograph made of me by my son, which, I daresay will do as well.—3

Your accounts of the Disa & Herschelea are excellent. & your drawings first-rate.4 I felt so sorry that such excellent work shd. remain locked up for an indefinite period in my portfolio, that you have made me break a solemn vow & I have drawn up from your notes (& selected 4 figures for woodcuts) an account for Linnean Soc.—5 I have enlarged a little & explained & introduced a few remarks.— I hope the Socy. will publish the paper, & if so I will send you spare copies.—6 The title is “On the Fertilisation of Disa grandiflora by Roland Trimen Eqr of the Colon. Off. C. Town: drawn up from notes & drawings sent to C. Darwin Eqr.” I hope that you will approve of this, & not object to anything in the little paper.—

I am very sorry to hear so poor an account of your health & that you have so little time to spare for the exercise of your admirable powers of observation.—7 I did not know all this; otherwise I shd. not have thought of asking for plants.8 Think not a moment more on subject.— Indeed I ought to work on other subjects.— Yet I am going to ask a favour, if you know any one who dabbles in Botany, viz for seed of any Cape Oxalis: several species present two forms, one with long pistil & short stamens, the other form with short pistil & longer stamens. It is of high interest to me to get seed of any such species.—9

To return to Orchids, I now believe that Hymenoptera & Diptera are generally the chief workers more than Lepidoptera.10 With respect to the limits of Rostellum; it can in most cases be told only conjecturally: in Disa the 2 discs (& no part of caudicle of pollinia) & the part which connects the 2 discs with the medial upward central fold or ridge, & whole face of column down to the two confluent stigmas, may all be considered as the rostellum or modified third stigma.—11

With sincere thanks & every good wish, Believe me, my dear Sir | Yours sincerely

C. Darwin


The year is established by the relationship between this letter and the letter from Roland Trimen, 16 March 1863.
Letter from Roland Trimen, 16 March 1863. Trimen’s photograph has not been found.
William Erasmus Darwin’s photograph of his father was taken in April 1861; the photograph is reproduced as the frontispiece to Correspondence vol. 9.
Trimen enclosed sketches of Disa grandiflora and Herschelia caelestis with his letter of 16 March 1863. The sketch of Disa grandiflora is reproduced facing p. 246. The sketch of Herschelia caelestis has not been found.
Trimen 1863. Trimen felt unequal to the task of writing up his observations on South African orchids for publication (see letter from Roland Trimen, 16 March 1863 and nn. 6 and 21).
Trimen 1863 was published in the Journal of the Proceedings of the Linnean Society (Botany) on 29 October 1863 (General index to the Journal of the Linnean Society).
In his letter to Trimen of 31 January [1863], CD asked for specimens of the orchid flowers Trimen had described so that he might examine them.
See letter from Roland Trimen, 16, 17, and 19 July 1863. CD had been investigating dimorphism in species of Oxalis since 1861 (see Correspondence vols. 9 and 10).
In Orchids, p. 39, CD had indicated that moths were the most effective pollinators of orchids. CD’s subsequent observations of the insect pollinators of orchids led him to conclude that species with ‘moderately long’ nectaries were pollinated by bees and flies (‘Fertilization of orchids’, p. 142; Collected papers 2: 139). See also letter to Roland Trimen, 31 January [1863].


CD has drawn up a paper from RT’s orchid notes on the fertilisation of Disa grandiflora for the Linnean Society [J. Linn. Soc. Lond. (Bot.) 7 (1863): 144–7].

CD would welcome seeds of any Cape Oxalis for his investigation of dimorphism.

Letter details

Letter no.
Charles Robert Darwin
Roland Trimen
Sent from
Source of text
Royal Entomological Society of London (Trimen papers, box 21: 56)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4179,” accessed on 22 February 2018,

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