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Darwin Correspondence Project

From Roland Trimen   16 March 1863

Colonial Office, | Cape Town.

16th. March, 1863.

My dear Sir,

I have received your kind letter of the 31st. January, and am very glad to hear that my Orchid sketches & obsns. interested you.1 You are quite right in supposing that there is no movement of the pollinia in the species I have described; I imagine that such motion is chiefly found in those species which have a cap of membrane over the viscid matter of the pollinia discs in situ,—certainly none of the Cape species that I have seen (all of which have the discs naked) present any phenomenon of the kind.2

I have been very much surprised, since my attention has been turned to the subject, at never meeting with a single insect (save the fly I have mentioned in connection with the Stellenbosch Disa (?))3 with a pollinium of a⁠⟨⁠ny⁠⟩⁠ kind attached to it. I have been collectin⁠⟨⁠g⁠⟩⁠ insects, especially Lepidoptera, ever since ⁠⟨⁠I have⁠⟩⁠ been out here,—and it certainly is ast⁠⟨⁠onishing⁠⟩⁠ that I have never fallen in with any ⁠⟨⁠pollinia-⁠⟩⁠laden moths or other insects.4

I am so little of a botanist ⁠⟨⁠    ⁠⟩⁠ that I really am not sure whether Orchideæ are propagated by the tubers from year to year:—is it so or is their increase only provided for by seed? In the latter case, many species would fare but badly, I should fancy.

I am fully sensible of the compliment you pay me in suggesting that I should write a paper on the fertilising contrivances in some genera of Cape Orchids for the Linnean or some other Society, but I am really not equal to it.5 The subject is so new to me, & my botanical knowledge so very slight, that I have not a sufficient foundation whereon to construct a scientific paper. I far prefer to be permitted to send you any material I may obtain, for you to work up and elucidate in that able manner which is so thoroughly your own.6 I trust that your half-expressed fears that you would not be able to publish again on the Orchid subject may prove unfounded,7 and that I may be able to ⁠⟨⁠con⁠⟩⁠tribute something more to induce you to ⁠⟨⁠con⁠⟩⁠tinue yr. illustrations of a subject which ⁠⟨⁠    ⁠⟩⁠ to have hitherto been but “dimly ⁠⟨⁠    ⁠⟩⁠ ⁠⟨⁠an⁠⟩⁠d “little understood” by naturalists.8

⁠⟨⁠I am⁠⟩⁠ sorry to say my Nos. V & VI and ⁠⟨⁠    ⁠⟩⁠ ⁠⟨⁠Saty⁠⟩⁠rium are no longer in flower9   I shall take care to send you some flowers next Spring, if I am still in this locality10

I have sent you with this, through my brother,11 sketches of the structure of Disa grandiflora (the finest of S. African Orchids) and of Herschelia caelestis, Lindley, found last month on the mountains here.12 I have tried to colour these, but, having unthinkingly made the outlines on glazed paper, have not done as well I might. My brother Henry (71, Guildford St., Russell Sqre. W.C.) is very fond of Botany, and has read your book13 with much interest. I have therefore sent him these two drawings to inspect, and asked him to send them on to you.

You will, I am sure, be ready to make allowances for any roughness or irregularity of drawing in my sketches, when I tell you the disadvantages under which I work. To begin with, I am far from strong,—indeed, I came out here for the benefit of my health.14 Living out of Cape Town, I have to leave Wynberg at 12 past 8 every morning & do not get back after office till 5 or 6 p.m. One is in a very unfit state for work requiring minuteness & attention after six hours office work & 212 hours omnibus in this climate; and you can imagine how difficult it is to work with any satisfaction by fits & starts in the Office. What spare time I have, too, is very much occupied with entomology, and then, besides, I am told that I mustn’t stoop more than I can help, & must take so much exercise per diem. Forgive these details; I cannot help grumbling sometimes, & thinking how delightful it would be to have all my time to give to natural history. I generally find some consolation in the reflection that very many others are in a similar position—obliged to follow distasteful work for a living.15

I am not quite clear as to the term ‘rostellum’.16 I don’t know how much it is to be understood as including. The Cape Orchids do not appear to have that special rostellum you describe in many British species. If you write again, tell me, for instance, the limits of the rostellum in Disa grandiflora, if you are able to make it out from my drawings.17

I shall look out for Bonatea, but am afraid, from localities I have seen quoted, that the Genus does not occur here, but in the Eastern part of the Colony.18

I have ventured to enclose you my photograph,19 as a prelude to my request that you will do me the kindness of sending me yours. It is true the advantage will be on my side in such an exchange, for Cape photographs are usually execrable, & never good. But the enclosed is the best I can get, & people here say (with one exception) that they “would know who it was”—an unusual admission as regards S. African cartes de visite.

I am, my dear Sir, | Yours very truly | Roland Trimen.




A, Front view of flower, with posterior sepal almost wholly cut away.

B, Upper and front view of column, with labellum and basal portions of lateral sepals attached.

C, Front view of flower, with basal half of posterior sepal attached.

D, Side view of column, with petals and spur of posterior sepal attached.

E, Do. do. with lateral petals removed.

F, Back and under do. do., with lateral petals attached.

G, Do. do. do. removed.

H, Pollinium attached to steel point (1, side, 2, upper view).

pp, lateral petals; l, labellum; sp, spur of posterior sepal, containing nectar.

dd, viscid discs of pollinia; s, stigma.

CD annotations

2.00 I have … insects. 2.00] cross in margin, red crayon
8.00 If … drawings. 8.00] cross in margin, red crayon
Top of letter: ‘Oxalis seed’ pencil
diagram A] circled pencil; ‘B’ deleted pencil; ‘A’ pencil
diagram E] circled pencil; ‘E’ deleted pencil; ‘C’ pencil
diagram F] circled pencil; ‘F’ deleted pencil; ‘B’ pencil
diagram H] circled pencil; ‘H’ deleted pencil; ‘D’ pencil


Trimen’s initial letter to CD, which contained a manuscript account of his observations on South African orchids, has not been found (see letter to Roland Trimen, 31 January [1863] and n. 2). Some of Trimen’s observations were published in Trimen 1863 (see n. 6, below), but that paper contains no mention of the observation given here; however, in ‘Fertilization of orchids’, p. 144, CD reported: ‘Mr. Trimen informs me that he has seen a Dipterous insect, allied to Bombylius, frequenting the flowers [of Disa grandiflora]’ (Collected papers 2: 141). Stellenbosch is a town in what was then Cape Colony (now part of South Africa), about thirty miles east of Cape Town (Heilprin and Heilprin eds. [1931]).
Trimen 1863, p. 147, notes the infrequency with which the pollinia were observed to have been removed from Disa grandiflora.
In his letter to Trimen of 23 May [1863], CD reported that he had reworked Trimen’s observations on Disa grandiflora as a paper for the Linnean Society (Trimen 1863). See also nn. 20 and 21, below.
The source of these quotations, probably a review of Orchids, has not been identified.
In his letter of 31 January [1863], CD asked Trimen to send him flowers of several orchids previously described or drawn by Trimen.
Henry Trimen was a medical student at King’s College, London (DNB).
See enclosure and nn. 20 and 21, below. The remaining enclosures have not been found. Trimen refers to John Lindley, who named the orchid Herschelia caelestis.
Trimen emigrated to Cape Colony in 1858 (DSAB).
Trimen worked in the Colonial Secretary’s office for the Cape public service (DSAB).
Rostellum: a modified stigma, occurring in many orchids, which separates the stigmatic surface from the anthers in the column (a structure resulting from the fusion of the carpels and stamens) (see Penguin dictionary of botany). In Orchids, p. 6, CD wrote: Of the three pistils [carpels], which ought to be present, the stigma of the upper one has been modified into an extraordinary organ, called the Rostellum, which in many Orchids presents no resemblance to a true stigma. The rostellum either includes or is formed of viscid matter; and in very many Orchids the pollen-masses are firmly attached to a portion of its exterior membrane, which is removed, together with the pollen-masses, by insects.
Trimen refers to Orchids; however, the exact reference has not been found. See also letter to Roland Trimen, 23 May [1863].
See letter to Roland Trimen, 31 January [1863] and n. 12. Trimen later sent CD information on Bonatea speciosa (see Correspondence vol. 12, letter to Roland Trimen, 25 November 1864), and published a paper on the species (Trimen 1864). See also ‘Fertilization of orchids’, p. 157 (Collected papers 2: 154).
The photograph has not been found.
The enclosure, which includes watercolour sketches, is reproduced [in volume 11] facing p. 246.
The enclosure was evidently sent by CD to the Linnean Society of London, together with a letter, which has not been found, giving instructions about the reproduction of four of the diagrams in Trimen 1863 (see n. 6, above); the four diagrams circled and lettered by CD appear as woodcuts in Trimen 1863, p. 145. Trimen’s original labelling of these diagrams was altered, in an unknown hand, to a more sophisticated scheme used in publication. On the verso of the enclosure is an annotation, also in an unknown hand, which states: ‘No. 1558. | Drawings on wood to be | made by Mr. Fitch. | A/c. for drawing & cutting | block to be sent to Mr. Darwin. | Letters of reference to be | engraved on the block.’ The reference is to Walter Hood Fitch, a botanical artist at the Royal Botanic Gardens, Kew (R. Desmond 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–.

Desmond, Ray. 1994. Dictionary of British and Irish botanists and horticulturists including plant collectors, flower painters and garden designers. New edition, revised with the assistance of Christine Ellwood. London: Taylor & Francis and the Natural History Museum. Bristol, Pa.: Taylor & Francis.

DNB: Dictionary of national biography. Edited by Leslie Stephen and Sidney Lee. 63 vols. and 2 supplements (6 vols.). London: Smith, Elder & Co. 1885–1912. Dictionary of national biography 1912–90. Edited by H. W. C. Davis et al. 9 vols. London: Oxford University Press. 1927–96.

DSAB: Dictionary of South African biography. Edited by W. J. de Kock et al. 4 vols. Pretoria and Cape Town: Nasionale Boekhandel Beperk [and others]. 1968–81.

‘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.]

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.

Penguin dictionary of botany: The Penguin dictionary of botany. Edited by Elizabeth Tootill et al. Harmondsworth, Middlesex: Penguin Books. 1984.

Trimen, Roland. 1863. On the fertilization of Disa grandiflora, Linn.... drawn up from notes and drawings sent to C. Darwin, Esq., FLS, &c. [Read 4 June 1863.] Journal of the Proceedings of the Linnean Society (Botany) 7 (1864): 144–7.

Trimen, Roland. 1864. On the structure of Bonatea speciosa, Linn. sp., with reference to its fertilisation. [Read 1 December 1864.] Journal of the Linnean Society (Botany) 9 (1867): 156–60.


RT has sent his observations on orchids to CD. Has found only one case of an insect with a pollinium adhering to it.

Letter details

Letter no.
Roland Trimen
Charles Robert Darwin
Sent from
Colonial Office, Cape Town
Source of text
DAR 70: 180, DAR 178: 184
Physical description
4pp damaged †

Please cite as

Darwin Correspondence Project, “Letter no. 4046,” accessed on 27 November 2021,

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