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Darwin Correspondence Project

To M. T. Masters   [28 March – 5 April 1867]1

The explanation of the sterility of the seed-capsules of the Cypripedium sent to me I have little doubt lies in the circumstance of their having been fertilised by pollen taken from the same plant or seedling.2 I now know of a long series of cases in which various orchids are absolutely sterile when fertilised by their own pollen, (proved however to be as itself effective) but which can be easily fertilised by pollen taken from other individuals of the same species, or from other and quite distinct species.—3 These facts strike me as most remarkable under a Phy. point of view; & all point to the necessity with plants of regular or occasional [union] between distinct individuals of the same species.—

If these remarks are of the least value to you, with respect to the communication you can of course use them4

[Many thanks] for note.— I received Report & I forward to Hildebrand copy of his paper.—5

I am at present so busy that I have no time to carefully examine the interesting specimen which you have kindly sent me & which I return. From the remarkable fact, lately ascertained by Dr. H. that with many orchids the ovules do not become developed until many weeks or even months after the pollen-tubes have penetrated the stigma, it is not a little difficult to ascertain whether an orchid [four words illegible] [whether] the abortion of the female organs has started.6 Of course there is no difficulty in ascertaining the rudimentary condition of the pollen.


The date is established by the relationship between this letter and the letter from M. T. Masters, 28 March 1867, and by the fact that a finished version of the first paragraph of the letter was published in the Gardeners’ Chronicle, 6 April 1867 (Collected papers 2: 134–5).
With his letter of 28 March 1867, Maxwell Tylden Masters had enclosed a letter from A.D.B. to the Gardeners’ Chronicle and included specimens. Though A.D.B.’s letter only mentions sending barren seed-capsules of Cypripedium insigne flowers crossed with flowers from other species, the specimens may have been labelled differently, or else CD assumed that the author had also placed pollen from C. insigne stamens on the stigma of the same flower, and on the stigmas of flowers from the same plant.
CD refers to cases reported to him by John Scott, Fritz Müller, and others; he reported on them in Variation 2: 133–5. See Correspondence vol. 12, letter from John Scott, 28 March 1864, Correspondence vol. 14, letter from Fritz Müller, 1 December 1866, and this volume, letters from Fritz Müller, 1 January 1867 and 2 February 1867; see also letter to Fritz Müller, 7 February [1867] and n. 6.
See letter from M. T. Masters, 28 February 1867, n. 2.
See letter from M. T. Masters, 28 February 1867 and n. 4; the references are to the report, International Horticultural Exhibition 1866, Friedrich Hildebrand, and Hildebrand 1866a.
CD refers to data presented in Hildebrand 1863 and 1865; there are lightly annotated copies of these papers in the Darwin Pamphlet Collection–CUL. CD reported Hildebrand’s results in Variation 1: 402–3, ‘Fertilization of orchids’, p. 153, and Orchids 2d ed., p. 172. See also Correspondence vol. 11, letter from Friedrich Hildebrand, 16 July 1863, and Correspondence vol. 14, letter to Fritz Müller, 25 September [1866].


Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 26 vols to date. Cambridge: Cambridge University Press. 1985–.

‘Fertilization of orchids’: Notes on the fertilization of orchids. By Charles Darwin. Annals and Magazine of Natural History 4th ser. 4 (1869): 141–59. [Collected papers 2: 138–56.]

International Horticultural Exhibition 1866: International Horticultural Exhibition and Botanical Congress, held in London, from May 22nd to May 31st, 1866. Report of Proceedings. London: Truscott, Son, & Simmons.

Orchids 2d ed.: The various contrivances by which orchids are fertilised by insects. By Charles Darwin. 2d edition, revised. London: John Murray. 1877.

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


Discusses the orchid specimens received from MTM. Remarks on the self-sterility of Cypripedium and other orchids.

Letter details

Letter no.
Charles Robert Darwin
Maxwell Tylden Masters
Sent from
Source of text
DAR 96: 34–5
Physical description
Adraft 3pp

Please cite as

Darwin Correspondence Project, “Letter no. 5468,” accessed on 25 January 2020,

Also published in The Correspondence of Charles Darwin, vol. 15