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Darwin Correspondence Project

To M. T. Masters   8 July [1862]1

Down. | Bromley. | Kent. S.E.

July 8th

My dear Sir

You wrote me some little time since an extremely kind note,2 which makes me believe you will excuse me now troubling you.—

I have been experimenting largely on fertility of central peloric flower of Pelargonium, but do not yet know result;3 but I much wish to try some experiments on other peloric flowers. Have you a garden & have you by chance any peloric plants in it? If so I would ask you to try a few simple experiments for me.— Or can you tell me what seed I could sow another spring with a fair chance of getting peloric flowers? The wild yellow Linaria is, I believe, often peloric; but I do not know how I could get seed. Does any cultivated Linaria produce often peloric flowers.— Does the wild colombine produce a whole circle of nectaries? I suppose so.

Any suggestions would be valuable. My object is to see when a flower undergoes any great change of structure, whether its fertility with others of the same species & unaltered, remains the same.—

You will see it is with the forlorn hope of illustrating sterility of Hybrids.—4

My dear Sir | Yours very sincerely | C. Darwin


The year is established by the relationship to the letter from M. T. Masters, 12 July 1862.
Letter from M. T. Masters, [c. 15 May 1862].
On 11 May 1862, CD had begun a series of crossing experiments with different varieties of pelargoniums, in an attempt to fertilise the normally sterile peloric flowers (see the experimental notes in DAR 51 (ser. 2): 4–9, 12–13; see also letter to Daniel Oliver, 8 June [1862], and letter to Asa Gray, 1 July [1862]). The results of these experiments are given in Variation 2: 167. Masters was making a special study of plant morphology and teratology; in April 1860, he and CD had discussed CD’s claim in Origin, p. 145, that ‘in irregular flowers, those nearest to the axis are oftenest subject to peloria, and become regular’ (see Correspondence vol. 8, letter to M. T. Masters, 13 April [1860], and Correspondence vol. 9, letter to Journal of Horticulture, [before 18 June 1861]).
In Variation 2: 166–7, CD discussed the sterility of peloric flowers in pelargoniums and other plants in a section entitled ‘Monstrosities as a cause of sterility’. He noted that, while ‘[g]reat deviations of structure … sometimes cause plants to become sterile … in other cases plants may become monstrous to an extreme degree and yet retain their full fertility’, and concluded: ‘no general rule can be laid down; but any great deviation from the normal structure, even when the reproductive organs themselves are not seriously affected, certainly often leads to sexual impotence’. In the following chapter, CD sought to relate his findings regarding the factors affecting fertility and sterility to the case of hybrids (ibid., pp. 178–91). For CD’s interest in hybrid sterility, see Correspondence vol. 10, Appendix VI.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

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.

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


CD has been experimenting on the fertility of peloric flowers, with the forlorn hope of illustrating sterility of hybrids; seeks further plants or seeds.

Letter details

Letter no.
Charles Robert Darwin
Maxwell Tylden Masters
Sent from
Source of text
American Philosophical Society (Mss.B.D25.)
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 3645,” accessed on 2 March 2024,

Also published in The Correspondence of Charles Darwin, vol. 10