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Darwin Correspondence Project

To Daniel Oliver   13 March 1877

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

Mar 13. 1877

My dear Prof: Oliver,

I am very much obliged for your caution.1 The case stands thus; I had a plant formerly the early flowers of which never expanded & were of small but not quite uniform size; they produced fine capsules. I thought it was a case of arrested development & did not examine them closely. But when I found on the Ceylon specimens still smaller buds my opinion altered; in these the petals were reduced to excessively minute scales which adhered firmly to the bases of the shorter stamens. Small as these flower-buds were, the anthers had dehisced, & pollen-tubes penetrated the stigmas, which were less papillose than those on the perfect flowers.2 These several facts taken together seem to me to justify me in calling the closed flowers cleistogamic; but I should like to hear what you think. Should you be able to find any cleistogamic flowers on any trimorphic species it would interest me greatly to examine them. Hildebrand states in one of his papers that he found cleistogamic flowers on many sp of Oxalis, but he does not say whether they were trimorphic: I think I will write & ask him.3

With many thanks, | Yours sincerely | Charles Darwin


See Correspondence vol. 25, letter from Daniel Oliver, 12 March 1877 and n. 1. Oliver suggested that flowers of Oxalis sensitiva (a synonym of Biophytum sensitivum), which CD had suggested were cleistogamic, were probably arrested or imperfectly developed normal flowers.
CD added this information in his discussion of cleistogamy in Oxalis sensitiva in Forms of flowers, pp. 322–4. In addition to noting the smoother surface of the stigma, he also noted that less pollen was produced in the cleistogamic flowers and speculated that the pollen was more potent, since an abundance of seed was produced.
CD’s letter to Friedrich Hildebrand has not been found, but see Correspondence vol. 25, letter from Friedrich Hildebrand, 19 March 1877. Hildebrand discussed cleistogamy in Oxalis and other genera in Die Geschlechter-Vertheilung bei den Pflanzen und das Gesetz der vermiedenen und unvortheilhaften stetigen Selbstbefruchtung (Sexual division in plants and the law of avoidance and disadvantage of perpetual self-fertilisation; Hildebrand 1867, pp. 74–7).


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

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

Hildebrand, Friedrich. 1867a. Die Geschlechter-Vertheilung bei den Pflanzen und das Gesetz der vermiedenen und unvortheilhaften stetigen Selbstbefruchtung. Leipzig: Wilhelm Engelmann.


Discusses possible cleistogamic flowers in Oxalis.

Letter details

Letter no.
Charles Robert Darwin
Daniel Oliver
Sent from
Source of text
Newcastle University Special Collections (Spence Watson/Weiss Archive GB186 SW/6/7)
Physical description
4pp LS

Please cite as

Darwin Correspondence Project, “Letter no. 10891F,” accessed on 26 November 2022,