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Darwin Correspondence Project

To Roland Trimen   25 November 1864

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

Nov 25, 1864.

My dear Sir

Your paper arrived quite safe.1 I have read it with much interest, for I have long thought the Bonatea one of the most curious orchids in the world.2 Asa Gray has described in an American Habenaria a nearly similar contrivance with respect to the nectary as yours.3 I have sent your paper to Linn. Soc. & I hope it may be printed, but that of course I cannot say & it may be influenced by cost of engraving.4

With respect to the Satyrium I shd think that the pollen masses which you sent had been scraped off the head of some insect by the insect itself; I do not refer to the additional pollen-masses which you saw growing in their cases.5

Most of the Oxalis’ which you so kindly sent me flowered, but all with 2 exceptions presented one form alone.6 From what I know about Primula, I shd be astonished at the same bulb ever producing 2 forms. In the 2 exceptional cases, one bulb in each lot produced a distinct form; but I have very little doubt there ought to be 3 forms. I got some seed from one of the unions & have some feeble hopes that they may germinate.

If I have strength (for I keep weak) I shd like to make out oxalis, so if you have any opportunity I should still be very glad of seed.

Many thanks about Strelitzia   Would it be possible to get a plant of the kind that seeds, protected from the sugarbirds, with another plant unprotected near by?7 I am tired, & so will write no more.

With many thanks pray believe me | yours very sincerely | Ch. Darwin


CD refers to the manuscript of Trimen’s paper on Bonatea speciosa (Trimen 1864). CD had been able to obtain only one dried specimen of the orchid for his own research (see Orchids, p. 304). He encouraged Trimen to study the species in his letter to Trimen of 31 January [1863] (Correspondence vol. 11). An annotated copy of Trimen 1864 is in the Darwin Pamphlet Collection–CUL. CD cited Trimen’s description in ‘Fertilization of orchids’, p. 157 (Collected papers 1: 154), and Orchids 2d ed., pp. 76–7.
Because of its anomalous structure, Bonatea, together with the genus Habenaria, posed a problem for CD’s view that the labellum of orchids is always formed from one petal and two petaloid stamens (see Orchids, pp. 302–5, Correspondence vol. 9, letter to J. D. Hooker, [9 December 1861], and Correspondence vol. 10, letter to J. D. Hooker, 11 September [1862]; see also Orchids 2d ed., pp. 243–5).
CD refers to the description of Habenaria flava (also called Platanthera flava) in Gray 1863c, pp. 292–3. Like Bonatea speciosa, H. flava possessed a protuberance rising from the base of the labellum that compelled insects entering the nectary to pass on either side, and thus to touch one of the two viscid discs of the pollinia. CD cited Gray’s description in ‘Fertilization of orchids’, p. 148 (Collected papers 1: 145), and in Orchids 2d ed., pp. 76–7. See also Correspondence vol. 11, letter from Asa Gray, 27 January 1863.
The letter from Trimen has not been found. CD had received a description and drawings of Satyrium from Trimen in January 1863 (see Correspondence vol. 11, letter to J. D. Hooker, 30 January [1863] and n. 10, and letter to Roland Trimen, 31 January [1863]). CD had suggested that Trimen examine the species further; CD wished to test the hypothesis, presented in Orchids, pp. 50–3, that the accessibility of a flower’s nectar was linked to the rate at which the viscid matter on the pollinia set (see Correspondence vol. 11, letter to Roland Trimen, 16 February [1863] and n. 4).
No letter from Trimen discussing Strelitzia has been found; see, however, letter to Roland Trimen, 13 May 1864 and n. 8. Promeropidae, or sugarbirds, are a family native to South Africa, whose long, curved bills enable them to feed on nectar (Oxford dictionary of natural history). CD received a specimen of Strelitzia from Joseph Dalton Hooker in April 1865 (see Correspondence vol. 13, letter to J. D. Hooker, 13 April [1865]). In Cross and self fertilisation, p. 371 n., CD remarked that Strelitzia at the Cape of Good Hope was pollinated by Nectariniidae, another family of small birds with long, narrow, curved bills.


Has forwarded RT’s paper on Bonatea to the Linnean Society [J. Linn. Soc. Lond. (Bot.) 9 (1865): 156–60].

The Oxalis sent by RT flowered but CD has made out only two forms; he thinks there ought to be three, so would welcome more seed.

Letter details

Letter no.
Charles Robert Darwin
Roland Trimen
Sent from
Source of text
Royal Entomological Society of London (Trimen papers, box 21: 60)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4680,” accessed on 18 August 2019,

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