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Darwin Correspondence Project

To Joseph Dalton Hooker   12 January [1858]1

Down Bromley Kent

Jan. 12th

My dear Hooker

I want to ask a question which will take you only few words to answer.— It bears on my former belief (& Asa Gray strongly expressed opinion) that Pipilionaceous flowers were fatal to my notion of there being no eternal her-maphrodites.—2 First let me say how evidence goes: you will remember my facts going to show that Kidney Beans require visits of Bees to be fertilised. This has been positively stated to be case with Lathyrus grandiflorus, & has been very partially verified by me.—3 Sir W. Macarthur tells me that Erythrina will hardly seed in Australia without petals are moved as if by Bee.—4 I have just met statement that with common Bean, when the Humble-bees bite holes at base of flower & therefore cease visiting mouth of corolla “hardly a bean will set”.

But now comes a much more curious statement that 1842–43 “since Bees were established at Wellington (N. Zealand), Clover seeds all over the Settlement, which it did not before”. The writer evidently has no idea what the connexion can be.—5 Now I cannot help at once connecting this statement (& all the foregoing statements in some degree support each other, as all have been advanced without any sort of theory) with the remarkable absence of Papilionaceous plants in N. Zealand.—

I see in your list Clianthus, Carmichælia 4 species— A new genus, a shrub; & Edwardsia—(is latter Papilionaceous?)6 Now what I want to know, is, whether any of these have flowers as small as clover; for if they have large flowers they may be visited by Humble-Bee, which I think I remember do exist in N. Zealand;7 & which Humble Bees would not visit the smaller clovers.— Even the very minute little yellow Clover in England has every flower visited & revisited by Hive Bees, as I know by experience.—8 Would it not be a curious case of correlation if it could be shown to be probable that herbaceous & small Leguminosæ do not exist because when seeds washed ashore!!!9 no small Bees exist there. Though this latter fact must be ascertained! I may not prove anything, but does it not seem odd that so many quite independent facts, or rather statements should point all in one direction viz that Bees are necessary to the fertilisation of Papilionaceous flowers.

Ever yours | C. Darwin

My man is getting on with D. Candolle, but he has been unavoidably delayed a little.—10 R. Brown’s Prodromus N. Hollandiæ has so very few varieties, that I shd not dare to trust result, whatever it might be.—11


Dated by the relationship to the letter from J. D. Hooker, 15 January 1858. See also n. 12, below.
CD had long held the belief that hermaphrodite organisms must occasionally cross-fertilise. In 1856 he had asked Thomas Henry Huxley whether there were any permanently self-fertilising in-vertebrates (Correspondence vol. 6, letters to T. H. Huxley, 1 July [1856] and 8 July [1856]) and had discussed the problem of the apparent self-fertilisation of papilionaceous flowers like peas and beans with both Hooker and Asa Gray. CD refers to the letter from Asa Gray, [August 1857] (Correspondence vol. 6).
CD wrote about these experiments in a letter to the Gardeners’ Chronicle, published under the heading ‘Bees and fertilisation of kidney beans’ on 24 October 1857 (Correspondence vol. 6, letter to Gardeners’ Chronicle, 18 October [1857]).
CD had met William Macarthur, a member of the legislative council of New South Wales, in 1857 (see Correspondence vol. 6, letters to Syms Covington, 22 February 1857, and to Asa Gray, [after 15 March 1857]). Erythrina is a papilionaceous tropical shrub.
CD refers to an account published in the Gardeners’ Chronicle and Agricultural Gazette, 16 December 1843, p. 881, which included a quotation from a notice in the New Zealand Journal .
CD refers to Hooker’s Flora Novæ-Zelandiæ (Hooker 1853–5, 1: 49–50).
CD had visited New Zealand during the Beagle voyage in December 1835 (Correspondence vol. 1).
CD mentioned this fact in Natural selection, p. 68.
CD emphasised the words ‘when seeds washed ashore’ because he and Hooker had a long-standing disagreement about the possibility of seeds retaining the power to germinate after periods of immersion in salt-water. Hooker was sure that such accidental and occasional means of transport could not account for the colonisation of land by new plants, even though CD had conducted numerous experiments to confirm the possibility of such transport (see Correspondence vols. 5 and 6).
A reference to Ebenezer Norman, the master of the national school in Down village, who acted as CD’s copyist. In 1856 and 1857, Norman compiled lists of species from botanical catalogues for CD’s statistical researches into the incidence of varieties. Norman was at this time compiling lists of large and small genera from Candolle and Candolle 1824–73, several volumes of which CD had borrowed from Hooker in 1857 (see Correspondence vol. 6). CD’s calculations and lists are in DAR 15.2, 16.1, and 16.2. For CD’s statistical work, see Browne 1983, pp. 204–6.


Brown, Robert. 1810. Prodromus florae Novae Hollandiae et Insulae Van-Diemen, exhibens characteres plantarum. Vol. 1 (no more published). London: Richard Taylor.

Browne, Janet. 1983. The secular ark. Studies in the history of biogeography. New Haven, Conn., and London: Yale University Press.

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].

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

Hooker, Joseph Dalton. 1853–5. Flora Novæ-Zelandiæ. 2 vols. Pt 2 of The botany of the Antarctic voyage of HM discovery ships Erebusand Terror, in the years 1839–1843, under the command of Captain Sir James Clark Ross. London: Lovell Reeve.

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.


On papilionaceous flowers and CD’s theory that there are no eternal hermaphrodites. Connects this theory to absence of small-flowered legumes in New Zealand and the absence of small bees as pollinators.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 114: 220
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 2201,” accessed on 12 December 2019,

Also published in The Correspondence of Charles Darwin, vol. 7