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Darwin Correspondence Project

From J. D. Hooker   20 October 1873

Royal Gardens Kew

Oct 20/73.

Dear Darwin

A line only to say that I am at Nepenthes but it is a far more difficult affair than Drosera, because of the thickness of the tissues.1 The structure of the glands of the pouch below water mark is well made out & described & consists of globose glands analogous I take it to Drosera’s tops of hairs, lying in a semi-circular fold of the cuticle & half exposed. It is in these globose glands that I must look for the action.

The water is acid: it has been most carefully described by Voelcker & others & I have I find referred to many papers on anatomy of Nepenthes: my account of the species for DC. Prod. which is printed I believe, but not yet published.2

I have found rough copy & can send you a string of authors

I have written to Dublin for a Drosophyllum.

Neptunia I can get nowhere.3

The other things I will write about tomorrow.4

Ever yours affec | J D Hooker

CD annotations

4.1 I … nowhere. 5.1] scored red crayon
Bottom of letter: ‘Lathyrus | Nissolia | Frank to look at Desmodium again’5ink


CD had asked Hooker to carry out some experiments on Nepenthes (the tropical pitcher-plant; see letter to J. D. Hooker, 19 September [1873], and Insectivorous plants, pp. 97, 361, 452).
Hooker had written the section on Nepenthes for Augustin Pyramus and Alphonse de Candolle’s Prodromus systematis naturalis regni vegetabilis (Candolle and Candolle 1824–73, 17: 90–105); in it he cited Voelcker 1849, p. 233, and Voelcker 1850, p. 173, where Augustus Voelcker described his analysis of the composition of the fluid in the pitchers of Nepenthes. Hooker described some of his experiments on the digestive powers of Nepenthes in an address to the zoology and botany section of the British Association for the Advancement of Science on 21 August (J. D. Hooker 1874; reprinted in Nature, 3 September 1874, pp. 366–72).
Hooker would have written to the Botanic Garden in Dublin for a specimen of Drosophyllum lusitanicum (the Portuguese sundew or dewy pine); CD had obtained specimens in 1869 (see Correspondence vol. 17). CD discussed Neptunia oleracea (the sensitive neptunia or water mimosa) in Movement in plants.
The next extant letter from Hooker is that of 25 October 1873.
CD’s notes are for his letter to Hooker of 23 October [1873].


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

Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

Voelcker, Augustus. 1849. On the chemical composition of the fluid in the ascidia of Nepenthes. [Read 12 July 1849.] Transactions and Proceedings of the Botanical Society of Edinburgh 3 (1850): 233–40. [Also published in Annals and Magazine of Natural History 2d ser. 4: 128–36.]

Voelcker, Augustus. 1850. On the watery secretion of the leaves and stems of the ice-plant (Mesembryanthemum crystallinum L.). Annals and Magazine of Natural History 2d ser. 5: 171–3.


Describes work on Nepenthes – more difficult than Drosera.

Has written to Dublin for a Drosophyllum.

Letter details

Letter no.
Joseph Dalton Hooker
Charles Robert Darwin
Sent from
Source of text
DAR 103: 171–2
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9102,” accessed on 23 January 2022,

Also published in The Correspondence of Charles Darwin, vol. 21