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Darwin Correspondence Project

To J. D. Hooker   20 May [1860]1

Down Bromley Kent

May 20th

My dear Hooker

The following, I believe, are all the chief references on experiments on Cowslips &c. for Harvey.—2

H. C. Watson Loudon’s Mag of Nat. Hist. Vol. 3. 1830 p.217 p. 852. W. Herbert. Transact. Hort. Soc. Vol. IV. p. 193 Henslow Loudon’s Mag. of Nat. Hist. Vol. 3. 1830. p. 409 He succeeded in getting primrose from cowslip4 H. C. Watson. Phytologist Vol. 2. p. 217 p. 852. Vol 3. p. 43.—5 Sidebotham Phytologist vol. 3. p. 703.6

Notwithstanding, the amount of evidence from witnesses who experimentised with hostile bias, I cannot avoid sometimes suspecting error.— No experiment is good unless plants protected by gauze or some other similar protection.—   I think Mr Sidebotham alone took such pains; yet for some unknown cause H. C. Watson sneers at his experiments.—   Mr Doubleday has often tried, & has found no variation.7 I reared lots of Primroses from manured primroses with no variation.—   I have now got cowslips under gauze, which I fertilize with care. Nevertheless looking through all the above accounts (& I have some loose corroborative facts) the evidence does seem overwhelming that they are varieties. The case does not half please me, as I remember saying to you, it does not work well in with nat. selection—it is rather too sudden a jump.—especially the adaption to different climatal ranges.— I am inclined by conjecture to look at cowslip as the modified descendant of Primrose; & that the seeds from the cowslip do not simply vary, but revert back in different degrees to primrose. Most of the experiments have been made on cowslips & oxlips.—   on this notion, the case would be more intelligible.

Yours affect | C. Darwin

I have received long copy of M.S. verses from some anonymous author, highly laudatory, yet partly quizzing the Origin.—   They are from some Botanist. I suspect Dr Boott.—8 Does he write verses?

Etty keeps just the same, poor little thing, now 3 week, wearing Fever. What a world it is—9


Dated by the reference to Henrietta Emma Darwin’s continuing fever.
William Henry Harvey had asked Hooker to obtain information from CD about hybridisation among Primula species (see L. Huxley ed. 1918, 1: 516–20). This phenomenon had been cited as support for CD’s view of intermediate gradations between varieties becoming sufficiently distinct that the forms could be judged as different species (see Spectator, 21 April 1860, p. 380).
Herbert 1822. CD cited this paper frequently in discussions of hybridisation in the manuscript of his ‘big book’ on species (Natural selection).
Henslow 1830.
Watson 1847.
Sidebotham 1849. CD discussed both this paper and Watson 1847 in Natural selection, pp. 130–3.
See letters from Henry Doubleday, 3 May 1860 and 16 May 1860.
The verses have not been found. Francis Boott’s theological beliefs had been shaken following his reading of Origin (see letter from Francis Boott, 29 February 1860). For CD’s opinion of Boott’s response to Origin, see the letter to J. D. Hooker, 3 March [1860].
Henrietta Emma Darwin had been very ill since 28 April 1860 (Emma Darwin’s diary).


Herbert, William. 1822. On the production of hybrid vegetables; with the result of many experiments made in the investigation of the subject. Transactions of the Horticultural Society of London 4: 15–50. [vols. 2,5,8]

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.

Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.

Sidebotham, Joseph. 1849. Experiments on the specific identity of the cowslip and primrose. Phytologist 3 (1848-9): 703–5. [Vols. 8,9]


Gives references to experiments on cowslip for W. H. Harvey.

Suggests possible sources of error in results. Feels evidence is overwhelming that cowslip and primrose are varieties.

Has received laudatory verses on the Origin from some botanist; suspects Francis Boott.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
Archives of the New York Botanical Garden (Charles Finney Cox Collection)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 2811,” accessed on 1 March 2021,

Also published in The Correspondence of Charles Darwin, vol. 8