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Darwin Correspondence Project

To Daniel Oliver   8 October [1861]1

Down. | Bromley. | Kent. S.E.

Oct 8th

My dear Sir

I am perfectly ashamed to trouble Hooker again.— Would you have kindness to look at well-opened flower of Stanhopea saccata & see whether any nectar is in hollowed out base or cup of Labellum; or in other species of Stanhopea, if they have hollowed out base or cup to Labellum.—

I have particular reason to enquire; but I daresay the plant will have none, though it ought to have some.—2 But Nature, as Agassiz says, does not lie,3 & therefore it must have nectar,—else a theory of mine is wrong which is clearly impossible!—

In Haste | Ever yours | C. Darwin


The idea that Stanhopea flowers ‘ought’ to have nectar in the base of the labellum is explained in Orchids, pp. 282–3: ‘As in Epipactis the cup at the base of the labellum serves as a nectar-receptacle, I expected to find that the analogous cup in Stanhopea, Acropera, &c., would serve for the same purpose; but I never could find a drop of nectar in it.’
CD was fond of quoting this aphorism attributed to Louis Agassiz. See, for example, Correspondence vol. 6, letter to Asa Gray, 1 January [1857].


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.


Asks DO to look for nectar in Stanhopea saccata labellum. CD’s theory predicts nectar should be present, but afraid there is none.

Letter details

Letter no.
Charles Robert Darwin
Daniel Oliver
Sent from
Source of text
DAR 261.10: 31 (EH 88206014)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3279,” accessed on 19 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 9