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Darwin Correspondence Project

To George Bentham   12 December 1876

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

Dec 12. 1876

My Dear Mr Bentham,

I am very much obliged for your long & interesting letter.1 Restio seems a wonderful case.2 With respect to Boronia pinnata I have examined all the flowers which you have kindly sent me, but though there is some variability in the length of the stamens & pistils I can see no evidence of the existence of two distinct bodies of individuals. Therefore I do not think it would be worth spending your valuable time in searching for other specimens.3 I have been often deceived about heterostyled plants by several causes. Sometimes the pistil increases so much in length after two or three days, that young & old flowers seem heterostyled. Asa Gray thought Amsinckia was heterostyled, but it is only a case of great variability in the parts.4 Again A. de Candolle thought Asperula scoparia was heterostyled, but it is diœcious with rather large rudiments of the sexual organs.5 This morning I have been examining Ægiphila obdurata (which was named for me at Kew, perhaps by you)6 and instead of being heterostyled, like the two species which you sent me, it has become diœcious. I see in Steudel that two species of Ægiphila grow in India & the Phillipines: do you know whether these extra-American species are heterostyled like Æ mollis & elata?7 I ask because it is of some importance to discover whether heterostyled species of the same genus are found in distant parts of the world, as rendering it probable as rendering it probable that this structure is of ancient origin. If you know nothing of the extra-American species of Ægiphila, pray do not trouble yourself by sending any answer.

With very many thanks I remain, my dear Mr Bentham | Yours sincerely | Charles Darwin


Bentham had mentioned the genus Restio as an interesting case of separation of the sexes; see letter from George Bentham, 10 December 1876 and n. 5.
See letter from George Bentham, 10 December 1876 and n. 1; CD was trying to ascertain whether the species were heterostyled, and Bentham offered to send flowers in which the difference in stylar and staminal length was more apparent.
Gray had sent CD flowers of Amsinckia spectabilis (the seaside fiddleneck) in 1861 (Correspondence vol. 9, letter to Asa Gray, 11 December [1861]). After studying these specimens, CD concluded that the differences in forms could not be determined in dried flowers (‘Dimorphic condition in Primula, p. 95; see also Collected papers 2: 62), but, after observing live specimens, he concluded that they were variable (Correspondence vol. 11, letter to Asa Gray, 20 April [1863]; Forms of flowers, p. 110). For more on heterostyly in A. spectabilis, see Ray and Chisaki 1957.
Augustin Pyramus de Candolle discussed species of Asperula in Candolle and Candolle 1824–73, 4: 581–6, but Asperula scoparia was not mentioned; see also letter to J. D. Hooker, 11 December 1876 and n. 2, and Forms of flowers, pp. 285–6.
See letter from J. D. Hooker, 8 December 1876 and n. 3. Aegiphila obdurata is a synonym of A. obducta.
See letter to George Bentham, 8 December 1876; Bentham sent flowers of Aegiphila elata (tall spiritweed) and A. mollis (contra culebra) in 1864. Steudel 1841, 1: 29, lists A. diffusa from India and A. virburnifolia from the Philippines.


Candolle, Augustin Pyramus de and Candolle, Alphonse de. 1824–73. Prodromus systematis naturalis regni vegetabilis, sive enumeratio contracta ordinum generum specierumque plantarum huc usque cognitarum, juxta methodi naturalis normas digesta. 19 vols. Paris: Treuttel & Würtz [and others].

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. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

‘Dimorphic condition in Primula’: On the two forms, or dimorphic condition, in the species of Primula, and on their remarkable sexual relations. By Charles Darwin. [Read 21 November 1861.] Journal of the Proceedings of the Linnean Society (Botany) 6 (1862): 77–96. [Collected papers 2: 45–63.]

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

Steudel, Ernst Gottlieb. 1841. Nomenclator botanicus: seu: synonymia plantarum universalis, enumerans ordine alphabetico nomina atque synonyma, tum generica tum specifica, et a Linnaeo et a recentioribus de re botanica scriptoribus plantis phanerogamis imposita. 2d edition. 2 parts. Stuttgart and Tübingen: J. G. Cotta.


Has examined the specimens of Boronia pinnata. No evidence of two distinct bodies of individuals.

Asks whether extra-American species of Aegiphila are heterostyled.

Letter details

Letter no.
Charles Robert Darwin
George Bentham
Sent from
Source of text
Royal Botanic Gardens, Kew (GEB/1/3: Correspondence, Vol 3, Daintree–Dyer, (1830–1884) 720)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10714,” accessed on 17 May 2021,

Also published in The Correspondence of Charles Darwin, vol. 24