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Darwin Correspondence Project

To J. T. Moggridge   1[7] July [1864]1

Down Bromley,

July 12th.

My dear Sir

I must express my joy and thanks at my extraordinary luck and your kindness about the seeds.—2 Mr. Bentham tells me that he is almost sure some of the species are dimorphic;3 I fear, from the dried flowers, that T. Rollii cannot be so.— As the species, I presume, increase by bulbs, I meant by “different groups”, to dig up bulbs from different spots, but it was very obscurely expressed.4 As I see you well understand dimorphism, perhaps you know whether either species is dimorphic; if not so, pray give yourself no more trouble on subject.

The Primula is superbly dimorphic.—5

I have been experimenting on common oxlip and have quite convinced myself that it is a hybrid from Primrose and Cowslip, which must be viewed as two perfect species. Therefore I presume that the oxlip to which you refer is P. elatior of Jacq.— I intend next Spring to prove whether by test of fertility it is a distinct species.6

With cordial thanks for your great kindness, I remain | Yours very sincerely | C. Darwin


The date is established by the relationship between this letter, the letter from George Bentham, 10 July 1864, and the letter from J. T. Moggridge, 15 July [1864]. The copy is misdated. It is probable that the copyist mistook CD’s 7 for a 2.
With his letter of 15 July [1864], Moggridge included seeds and a dried specimen of Trichonema rollii.
See letter from J. T. Moggridge, 15 July [1864]. The letter to Moggridge containing CD’s original request has not been found.
CD eventually demonstrated that the common oxlip was a hybrid of Primula veris and P. vulgaris (see letter to J. D. Hooker, 10 June [1864] and n. 17, and that the latter were distinct species, as was the Bardfield oxlip (P. elatior) (see letter to J. D. Hooker, 13 June [1864] and n. 6, ‘Specific difference in Primula, pp. 437–51, and Forms of flowers, pp. 55–73).


Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.

‘Specific difference in Primula’: On the specific difference between Primula veris, Brit. Fl. (var. officinalis of Linn.), P. vulgaris, Brit. Fl. (var. acaulis, Linn.), and P. elatior, Jacq.; and on the hybrid nature of the common oxlip. With supplementary remarks on naturally produced hybrids in the genus Verbascum. By Charles Darwin. [Read 19 March 1868.] Journal of the Linnean Society (Botany) 10 (1869): 437–54.


Discusses dimorphism in flowers. Describes his experiments.

Letter details

Letter no.
Charles Robert Darwin
John Traherne Moggridge
Sent from
Source of text
DAR 146: 373
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4563,” accessed on 18 April 2021,

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