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Darwin Correspondence Project

From R. D. Fitzgerald   20 September 1875

Surveyor Generals Office | Sydney

20 Sep 75

Dear Sir

Please accept my best thank’s for your very kind and encouraging letter and for the present of your work on Insectivorous Plants, which I have just received and in the perusal of which I expect great pleasure.1 Nothing could have afforded me greater satisfaction than the expression of your approval.

There are many things I have made out respecting various species, which will I think interest you, and which I hope to be able to publish in succeeding parts. Respecting Dendrobium Hillii you suggest that the pollen of a distinct plant should be applied in order to try whether barrenness would be thereby overcome; but in fact D Hillii is not in the least barren from any other cause than that no pollen reaches the stigma.2 When its own or that of any other Dendrobium is placed on the stigma a capsule is readily produced. As to the Calli on Caladenia I have frequently examined specially whether they were attractive to insects as food; but could never find that they were eaten in preference to any other part of the flowers and I am convinced that the Caladenias are principally fertilised by large flies brought into contact with the anther and stigma by the spring of the labellum.3 I have absolutely observed such fertilisation in two instances one in a house and the other in the “bush”

I have just noticed a remark in “My Garden” by A Smee FRS which I think curiously supports my suggestion as to the method in which Angræcum sesquipedale may be fertilised. speaking of it he sais “having a long appendage which the crickets delight to eat making the flower look ridiculous” p. 302.4 I am in hopes that I may be able soon to send you the second part of the Orchids in which you will find remarks on our spiranthes that will I think interest you5

I remain Dear Sir | Yours truly | Robt D Fitzgerald

CD annotations

1.1 Please … approval. 1.4] crossed ink
2.4 but … stigma. 2.6] scored blue crayon
2.7 Caladenia] underl red crayon
Top of letter: ‘Read over introduction & rest of book marked’ pencil


See letter to R. D. Fitzgerald, 16 July 1875. Fitzgerald’s name appears on CD’s presentation list for Insectivorous plants (Appendix IV).
See letter to R. D. Fitzgerald, 16 July 1875 and n. 6. In his Australian orchids (Fitzgerald 1875–94, vol. 1, part 1: 2), Fitzgerald had described a specimen of Dendrobium hillii that from around 40,000 flowers produced not a single seed; he attributed the failure to mechanical obstructions to pollination. Dendrobium hillii is a synonym of D. speciosum var. hillii, the king orchid. There is an annotated copy of Fitzgerald 1875–94 (all seven parts of vol. 1, and parts 1, 3, 4, and 5 of vol. 2) in the Darwin Library–CUL (see Marginalia 1: 229–30).
CD had asked whether the calli (non-secreting glands) on the labellum of Caladenia (the spider orchid) were gnawed by insects (letter to R. D. Fitzgerald, 16 July 1875). In Orchids 2d ed., p. 89, CD quoted Fitzgerald’s description of a fly landing on the lip of a specimen of Caladenia dimorpha and transferring pollen from the anther to the stigma in its efforts to escape, and Fitzgerald’s conviction that some species of Caladenia were exclusively insect-pollinated (Fitzgerald 1875–94, vol. 1, part 1).
Fitzgerald refers to Alfred Smee and Smee 1872. In Fitzgerald 1875–94, vol. 1, part 1: 2, Fitzgerald had speculated that Angraecum sesquipedale (Darwin’s orchid)was pollinated not by insects with unusually long probosces to reach into the deep nectary (see Orchids, pp. 197–203), but by small insects that crawled in for refuge or ate their way in.
In Orchids 2d ed., pp. 114–15, CD referred to Fitzgerald’s description of self-fertilisation in Spiranthes australis in Fitzgerald 1874–94, vol. 1, part 2. Spiranthes australis is a synonym of S. sinensis (austral ladies tresses).


Fitzgerald, Robert David. 1875–94. Australian orchids. 2 vols. Sydney: Thomas Richards.

Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.

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.

Smee, Alfred. 1872. My garden: its plan and culture together with a general description of its geology, botany, and natural history. 2d edition. London: Bell and Daldy.


On fertilisation in certain orchids.

Letter details

Letter no.
Robert David Fitzgerald
Charles Robert Darwin
Sent from
Source of text
DAR 164: 130
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 10161,” accessed on 24 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 23