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Darwin Correspondence Project

From George Bentham   30 April 1868

25, Wilton Place, | S.W.

April 30/68

My dear Mr Darwin

Many thanks for the trouble you took in writing to me and sending the pamphlets which I shall return in a few days.1 Hildebrand’s methodical summary of his observations on Dichogamy is very useful.2 As soon as numerous detached facts have been recorded on any particular subject it becomes most essential to have them brought together for those who want to make use of them. Delpinos dichogamic observations are also a collection of all the cases he has met with but have you read his Pensieri (or had it read for you as I observe you say do not read Italian)3 Chiefly verbiage and no facts—all speculation. A great admirer of yours—of your views of affinity depending on descent—firmly believing that all plants phoenogamic and cryptogamic are all descended from one type—agreeing with you in all but in your great and ruling principle of natural selection which he utterly rejects—misrepresents you in supposing you to attribute variation to chance—and substitutes for natural selection—a plasmatory principle endowed with intelligence which he attributes to plants—and believes that under the guidance of this principle every plant modifies the form colour scent etc of its own flowers in order to attract the particular insect it requires to fertilise it—and as the degree of intelligence is so different in different animals (contrasting for instance the cleverness and intelligence of hymenoptera with the stupidity of Sarcophaga carnaria in being so grossly deceived by the putrid-meat look and smell of Stopelea flower)4—so in plants the degree of intelligence displayed in moulding their flowers is very various.

My object in writing to you now is however to beg a favor of you. Could you lend me for a few days Sprengel’s Entdeckte Geheimniss der Natur which I cannot find anywhere— It is neither at the Royal nor at the Linnean Society nor yet at Kew.5 Also can you tell me what is Häckel’s “Generelle Morphologie der Organismen” which is said to be a remarkable working out of your views.6

Amongst dichogamists I meet with no explanation of such cases as those of Viola odorata canina and all that set (not the V. tricolor set)7 in which the showy spring flowers are generally (indeed I believe in some species universally) sterile and the very inconspicuous petalless and summer flowers alone bear seeds   Hildebrand alludes indeed to the mode of fecundation of the petalless flowers of Oxalis acetosella and Viola odorata—but what is the part in the economy of the plant acted by the numerous showy flowers which appear at a different season?8

Ever yours sincerely | George Bentham

CD annotations

2.1 Could … anywhere— 2.3] scored blue crayon
3.1 Amongst … that set 3.2] scored blue crayon
3.6 but … season? 3.7] scored blue crayon
Verso of letter: ‘Rutemeyer | Gaudry’9 pencil


In his letter of 22 April 1868, CD promised to send some pamphlets on cross-fertilisation, but did not mention specific titles. See n. 2, below.
CD evidently sent Hildebrand’s book on sexual division in plants (Hildebrand 1867a). Bentham may also refer to Friedrich Hildebrand’s papers on Corydalis cava and Salvia (Hildebrand 1866a, 1866b, and 1866–7; see letter to George Bentham, 22 April 1868 and n. 6).
Federico Delpino had sent CD two papers on dichogamy (Delpino 1867a and 1867b; see Correspondence vol. 15, letter from Federico Delpino, 5 September 1867 and n. 2). CD’s annotated copies (together with three additional pages of notes affixed to Delpino 1867a) are in the Darwin Pamphlet Collection–CUL. An offprint of the work Bentham refers to, ‘Pensieri sulla biologia vegetale’ (Thoughts on plant biology; Delpino 1867c) is also in the Darwin Pamphlet Collection–CUL, but was probably sent to CD in 1869 (Correspondence vol. 17, letter from Frederico Delpino, 22 August 1869).
Sarcophaga carnaria is the flesh-fly. Bentham also refers to the genus Stapelia, members of which have large, often star-shaped, rotten-smelling flowers.
Bentham refers to Christian Konrad Sprengel’s book Das entdeckte Geheimniss der Natur im Bau und in der Befruchtung der Blumen (The secret of nature discovered in the structure and fertilisation of flowers; Sprengel 1793). He also refers to the libraries of the Royal Society of London, the Linnean Society, and the Royal Botanic Gardens, Kew.
The reference is to Ernst Haeckel’s work on the general morphology of organisms (Haeckel 1866).
Viola odorata is the sweet violet; V. canina the heath dog violet; V. tricolor heartsease or wild pansy. In Forms of flowers, pp. 314–21, CD discussed the cleistogamic flowers of several species of Viola including V. odorata and V. canina, and noted that V. tricolor did not produce cleistogamic flowers.
See Hildebrand 1867a, p. 74. Oxalis acetosella is wood sorrel.
CD refers to Ludwig Rütimeyer and Albert Gaudry. See letter to George Bentham, 1 May [1868] and n. 10.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 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.

Haeckel, Ernst. 1866. Generelle Morphologie der Organismen. Allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie. 2 vols. Berlin: Georg Reimer.

Sprengel, Christian Konrad. 1793. Das entdeckte Geheimniss der Natur im Bau und in der Befruchtung der Blumen. Berlin: Friedrich Vieweg.


Discusses Hildebrand

and criticises Delpino.

Asks to borrow C. K. Sprengel’s Entdeckte Geheimniss der Natur [1793].

Botanists have no explanation of the case of Viola odorata and other showy flowers being sterile while inconspicuous ones bear seed.

Letter details

Letter no.
George Bentham
Charles Robert Darwin
Sent from
London, Wilton Place, 25
Source of text
DAR 160: 161
Physical description
3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 6147,” accessed on 19 February 2020,

Also published in The Correspondence of Charles Darwin, vol. 16