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Darwin Correspondence Project

From John Scott   28 May [1863]1

Botanic Gardens [Edinburgh]

May 28th.


I enclose copy from the Edinburgh Courant, of notice of late meeting of the Bot. Soc.2 The abstract of paper on Orchid I made at the request of the Secretary;3 as I did it hurriedly with pencil, however, he has copied it very incorrectly; indeed in one place it is impossible to understand it at all. This I have attempted to correct in enclosed copy.— Similar mistakes will therefore be occurring in Gard. Chron.4 It is very teasing.

You will perhaps be surprised at title now given. I think it is much less appropriate than the one I originally intended—Individual Sterility of Orchids: which clearly defined its nature.5 Prof. Balfour proposed that now substituted: it has given it the appearance of a simple record of experiments destitute of any theoretical application.6 The general reader at least will be somewhat surprised on passing from title to introductory remarks on Sterility! I was also anxious to emphasize the possibly individually limited nature of sterility manifested under my experience. Some may now be inclined to attribute to me a belief in the general sterility of their cultivated individual representatives; which is far from the truth. Indeed—as I have already stated—I am inclined to suppose that this will rarely if ever be the case—structural dimorphism of course excepted— certainly in cases of Passiflora & Lobelia fulgens, it has only a limited application. Individual plants of the latter, as well as the former, produce seeds with own pollen—while others are absolutely self-sterile.7

Perhaps farther illustrations may be afforded after the notice of my experiments in Gard. Chron. In the event of such it will be necessary to state the existence of an individual sterility; otherwise, they might be thought to disprove mine: as I have made no special allusion to it.

Will you kindly excuse the liberty I take, in asking you—time & health permitting—to reply and afford an explanation of the different results.8

In notice you will also find a curious case of variation—at least the writer seems to consider it such—9 Perhaps, I am wrong, in regarding it as of a similar nature to the well-known laburnum case. 10 The specimens sent are much mutilated—from careless packing—which prevents satisfactory comparisons; otherwise we might have been better able to judge. Differing, however, as it does in so many characters from the supposed normal form—more evidence is certainly required before we can regard it as simply a “bud-variation”.11

I remain | Sir | Yours very respectfully | J. Scott

CD annotations

2.1 You will … nature 2.3] scored brown crayon
2.12 Individual plants … self-sterile 2.13] scored brown crayon
5.1 In notice … variation—] cross in margin, brown crayon


The year is established by the reference to the Edinburgh Evening Courant of 28 May 1863 (see n. 2, below).
Scott refers to the Edinburgh Evening Courant, 28 May 1863, p. 8, which carried an article on the meeting of the Botanical Society of Edinburgh on 14 May 1863. See also n. 3, below.
Scott refers to an abstract of his paper on pollination experiments with orchids, which was read before the Botanical Society of Edinburgh on 14 May 1863. The paper was later published in full in the transactions of the society (Scott 1863a). There is a copy of Scott 1863a in the Darwin Pamphlet Collection–CUL. The honorary secretary of the Botanical Society of Edinburgh was Robert Kaye Greville (Medical directory 1863).
An abstract of Scott’s paper on pollination experiments with orchids (see n. 3, above), also appeared in the Gardeners’ Chronicle, 13 June 1863, p. 558. See also letter from John Scott, [3 June 1863].
Scott’s paper was entitled ‘Experiments on the fertilisation of orchids in the Royal Botanic Garden of Edinburgh’ (Edinburgh Evening Courant, 28 May 1863, p. 8). The paper demonstrated the sterility of several species of Oncidium when flowers were pollinated with pollen from the same plant (‘individual sterility’), and also showed that the same plants could be successfully fertilised when pollinated with pollen from a different species of Oncidium.
As regius keeper of the Royal Botanic Garden, Edinburgh, John Hutton Balfour was Scott’s employer, as well as a leading figure in the Botanical Society of Edinburgh. Scott’s main theoretical point was that as there were varying degrees of sterility in the vegetable kingdom, which did not necessarily conform to recognised systematic affinities, Thomas Henry Huxley’s use of sterility as the crucial test of the origin of species by natural selection (T. H. Huxley 1863b, pp. 107–8) was flawed (Scott 1863a, pp. 543–5). For a discussion of the background to this debate, see also Correspondence vol. 10, Appendix VI.
Scott expressed similar reservations about the general applicability of observations documenting own-pollen sterility in Passiflora and Lobelia in his letters to CD of 3 March 1863 and 21 March [1863]. CD had encouraged Scott to experiment with Passiflora and Lobelia to provide data on plants more easily fertilised by the pollen of another species than by their own pollen (see Correspondence vol. 10, letters to John Scott, 19 November [1862] and 11 December [1862] and n. 21). He sent further information to assist Scott in his experiments on Passiflora in March 1863 (see letter from John Scott, 3 March 1863, and letter to John Scott, 6 March 1863). Scott published his observations on sterility in self-pollinated Passiflora in Scott 1864d; they are summarised in Variation 2: 137–8. See also letter to John Scott, 31 May [1863] and n. 7.
The reference is to a letter from William Bell, read at the meeting of the Botanical Society of Edinburgh, 14 May 1863, describing a plant of Hibiscus tricuspis that produced branches bearing leaves and flowers widely different from the normal forms (Edinburgh Evening Courant, 28 May 1863, p. 8).
Cytisus adami, Adam’s laburnum, was thought to be a hybrid between C. laburnum and C. purpureus, two very distinct species. This tree was described in Variation 1: 387: ‘Throughout Europe, in different soils and under different climates, branches on this tree have repeatedly and suddenly reverted to both parent-species in their flowers and leaves’. CD did not regard this as a case of bud-variation (Variation 1: 389–91).
CD defined bud-variation as ‘sudden changes in structure or appearance which occasionally occur in full-grown plants in their flower-buds or leaf-buds’ (Variation 1: 373). CD did not include the case of Hibiscus tricuspis in the chapter on bud-variation in Variation (ibid., pp. 373–411). CD had asked Scott to send examples of bud-variation (see letter to John Scott, 16 February [1863] and n. 7).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Medical directory: The London medical directory … every physician, surgeon, and general practitioner resident in London. London: C. Mitchell. 1845. The London and provincial medical directory. London: John Churchill. 1848–60. The London & provincial medical directory, inclusive of the medical directory for Scotland, and the medical directory for Ireland, and general medical register. London: John Churchill. 1861–9. The medical directory … including the London and provincial medical directory, the medical directory for Scotland, the medical directory for Ireland. London: J. & A. Churchill. 1870–1905.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Sends abstract from Edinburgh Courant of his orchid sterility paper [see 4087]. Balfour altered title to obscure its theoretical nature.

Sends specimens showing curious variation.

Letter details

Letter no.
John Scott
Charles Robert Darwin
Sent from
Edinburgh Botanic Gardens
Source of text
DAR 177: 92
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4190,” accessed on 17 January 2021,

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