To Asa Gray   31 May [1863]1

Down Bromley Kent

May 31st

My dear Gray.

I was very glad to receive your Review of Decandolle a week ago.2 It seems to me excellent & you speak out, I think, more plainly in favour of derivation of species, than hitherto, though doubtfully about natural selection.3 Grant the first, I am easy about the second. Do you not consider such cases as all the Orchids next thing to a demonstration against Heer’s view of species arising suddenly by monstrosities:4 it is impossible to imagine so many coadaptations being formed all by a chance blow. Of course Creationists would cut the enigma.

What an indomitable worker you are! Why these Reviews, supposing I were to attempt them, would take me a month’s work.5 I have written twice to you not very long ago,6 & sent 2 copies of my Linum paper;7 but they & letter were sent about time of sailing of Anglo-Saxon, & were perhaps lost.8 I only remember in my letter telling you how right you were about fertilisation of Cypripedium.9 Of the species sent by you, C. acaule alone has flowered & has puzzled me. Mitchella, alas, does not look very healthy with all our care.10 If you see & know Mr. Scudder please thank him particularly for his interesting paper on Pogonia, which I was very glad to read.—11

To return to your Review: I was very glad to see your Remarks in answer to Falconer on Phyllotaxy;12 I infer you cannot explain why there are not intermediate angles. I have been looking at Nageli’s work on this subject,13 & am astonished to see that angle is not always the same in young shoot when leaf-buds are first distinguishable as in full-grown branch. This shows, I think, that there must be some potent cause for those angles which do occur: I daresay there is some explanation as simple as that for the angles of the Bees-cells.—14

You allude to Saporta’s work;15 Alp De Candolle sent me a copy of part of letter from him, in which he expressed strong belief that N. Selection would ultimately be triumphant in France, though now quite ignored.—16

I have nothing to tell you about my own doings: I work every day, that I can, on my big book & am now at all causes of sterility under domestication & cultivation.17 I have got such an immense collection of facts, that the work though laborious & slow interests me, as I can generally come to some sort of conclusion. There never will be a man who will read my big book; it will be a sort of encyclopedia on special cases.—18

I have been looking again at the imperfect flowers of Oxalis & Viola: I was entirely wrong in supposing that in Oxalis the perfect flowers required insect-aid for fertilisation; so this view is knocked on the head. Viola, however, does require insects.19 I must yet stick to my opinion that the imperfect flowers of Viola at least deserve to be ranked as something more than mere precocious flowers. In V. canina only 2 anthers are developed; the pollen-grains are smaller—the pistil widely different in shape; no nectar-appendages to the two fertile stamens & no spur.—20 Remember, if you can get them, seed of Campanula perfoliata.—21

I suppose you are very busy, & I suppose the whirlwind of public affairs must waste much of your time. Do not think of writing to me unless you have any leisure; though a letter from you is always a real pleasure to me. I suppose there are few human beings in England who see so few persons out of their own family as I do.—

Good night. | Yours most sincerely | C. Darwin

I have been observing common Broom: hardly any orchid shows prettier adaptation to insects which are necessary for its fertilisation:— The upper & lower surface of thorax of Bees gets dusted with pollen, & first the stigma rubs the upper side of thorax & afterwards is rubbed by the lower side of thorax.—22

1
The year is established by the reference to Gray’s review of A. de Candolle 1862a (see n. 2, below), published in May 1863.
2
Gray’s review of A. de Candolle 1862a appeared in the American Journal of Science and Arts (A. Gray 1863d). There are annotated copies of A. de Candolle 1862a and A. Gray 1863d in the Darwin Pamphlet Collection–CUL.
3
In his review, Gray argued that the views adopted by Alphonse de Candolle were representative of a general consensus among eminent naturalists, that is, that species had come into existence coincident in time and space with pre-existing and closely allied species, and that the distribution and origin of congeneric species had come to be ‘regarded as something derivative’ (A. Gray 1863d, pp. 437–8). On natural selection, Gray stated his opinion that: ‘something more than natural selection is requisite to account for the orderly production and succession of species’ (ibid., p. 440).
4
In his review of A. de Candolle 1862a, Gray noted that Candolle supported the concept of the ‘derivation of species’, but had been unclear as to whether he viewed that process as one of slow and very gradual change, following CD’s view of the origin of species, or whether he believed, with the Swiss palaeobotanist Oswald Heer, that sudden, inexplicable change, and the production of monstrosities, were causal factors in the production of new species (A. Gray 1863d, p. 438). Heer’s views on the origin of new species were developed within the context of his studies of Tertiary floras (Heer 1855–9).
5
Gray was a regular reviewer for the American Journal of Science and Arts, a bimonthly publication.
7
Gray acknowledged the receipt of ‘Two forms in species of Linum’ in his letter to CD of 26 May 1863. For CD’s presentation list for this paper, see Correspondence vol.11, Appendix IV.
10
Gray had sent CD specimens of Cypripedium acaule and Mitchella repens to grow and examine for pollination mechanisms and heterostyly, respectively; CD received the plants at the end of December 1862 (see Correspondence vol. 10, letter from Asa Gray, 9 December 1862, and letter to J. D. Hooker, 29 [December 1862]). For CD’s research on the genus Cypripedium, including C. acaule, see the letter from Asa Gray, 26 May 1863 and nn. 17, 18, and 20. CD had been interested in obtaining specimens of Mitchella repens since Gray suggested that the species would be a good case-history for research on dimorphism (see Correspondence vol. 9, letter from Asa Gray, 11 October 1861, and Correspondence vol. 10, letters to Asa Gray, 9 August [1862] and 6 November [1862]).
11
The reference is to Scudder 1862c, which discussed the structure and manner of pollination of the orchid Pogonia ophioglossoides. CD cited Scudder 1862c in Orchids 2d ed., p. 86. Samuel Hubbard Scudder was Gray’s colleague at Harvard University.
12
In reviewing Hugh Falconer’s assertion that phyllotaxy was governed by fixed physical laws (Falconer 1863a, p. 80), Gray pointed out that there were two distinct ‘species’ of phyllotaxy, alternate leaves and verticillate leaves, and that there could be a change from one to the other on the same stem. Gray commented: ‘Here is a change from one fixed law to another, as unaccountable, if not as great, as from one specific form to another’ (A. Gray 1863d, p. 440). See also letters to J. D. Hooker, [9 May 1863] and n. 10, and 29 May [1863] and n. 12, and letter from Asa Gray, 26 May 1863 and nn. 24 and 25.
13
The reference is to the first part of Nägeli 1858–68. See letter from J. D. Hooker, [13 May 1863].
14
CD believed the angles of the walls of bee-cells had been governed by natural selection for the purpose of economising wax (Origin, pp. 224–35).
15
Gray discussed Saporta 1862a in A. Gray 1863d, pp. 440–1.
16
In the letter to Alphonse de Candolle, 31 January [1863], CD acknowledged receiving news of the views of Gaston de Saporta. Neither the letter from Candolle, nor that from Saporta, has been found. Saporta was the principal founder of evolutionary palaeobotany in France (Tort 1996, pp. 3771–4). On the reception of Origin in France, see also Conry 1974, Farley 1974, Stebbins 1974, and Corsi and Weindling 1985.
17
CD worked on a draft of the chapters for Variation on crossing and sterility (Variation 2: 85–191) between April and mid-June 1863 (see ‘Journal’ (Correspondence vol. 11, Appendix II)).
18
CD may refer to Variation (see n. 17, above), published in two volumes in 1868; it was the first part of a planned three-part ‘big book’ on the evolution of species (see Origin, p. 1, and Correspondence vol. 7, letter to T. H. Huxley, 16 December [1859], and letter to John Murray, 22 December [1859]). Variation was the only part of the ‘big book’ to be published during CD’s lifetime; the remaining draft chapters were published posthumously as Natural selection.
19
In the letter to the Journal of Horticulture and Cottage Gardener, [17–24 March 1863], CD had written: But it is known that several plants, such as Violets, Campanulas, Oxalis, &c., produce two kinds of flowers: one sort adapted for self-fertilisation, and the other sort for fertilisation by insect agency or other means. CD made further observations on Oxalis acetosella between 31 March and May 1863 (see letter to John Scott, 12 April [1863], and experimental notes in DAR 111: 46 and DAR 109: B6). CD initially believed the ‘perfect flowers’ of the species to be heterostyled and hence adapted to cross-pollination by insects, but later concluded that the species was homostyled (see Forms of flowers, p. 182). CD’s observations on Viola were published in Forms of flowers, pp. 315–21 and 336. CD had been experimenting on ‘imperfect’ (cleistogamic) flowers of Oxalis and Viola since 1862; he summarised his provisional conclusions on their function in the letter to Asa Gray, 26[–7] November [1862] (Correspondence vol. 10). There is a series of experimental notes on ‘imperfect’ flowers of Viola and Oxalis, dated between 15 April 1863 and 15 May 1863, in DAR 111: 8–11, 46.
20
The flowers of Viola canina are described in Forms of flowers, pp. 314–17. CD used the case of ‘imperfect’ (cleistogamic) flowers in Viola as an example of how elements of flower structure, superfluous to the pollination mechanism, could gradually disappear (Forms of flowers, p. 336).
21
CD had asked for seeds of this species, also called Specularia perfoliata, in connection with his research on cleistogamy (see letter to Asa Gray, 20 March [1863] and n. 5).
22
CD’s notes on the pollination mechanism of the common broom (Cytisus scoparius) are given in G. Henslow 1866 and Cross and self fertilisation, pp. 163–4. See also letter to J. D. Hooker, 29 May [1863].

Manuscript Alterations and Comments

1.7 Of course … enigma.] added
2.2 to you] interl
3.4 when … distinguishable 3.5] interl
5.6 cases.] above del ‘facts.’
6.4 of Viola at least 6.5] interl
6.7 nectar-] interl
6.8 get them,] interl
9.2 which are … fertilisation:] interl
9.3 of Bees] interl
9.3 upper side] above del ‘top’

Please cite as “DCP-LETT-4196,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-4196