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Darwin Correspondence Project

To J. D. Hooker   15 [May 1862]1

Leith Hill Place, Dorking (where we stay till this day week)

Thursday 15

My dear Hooker

I would not have sent Leschenaultia, had I known that Sir William was away, & you so busy;2 for Emma has only just shown me Mrs. Hooker’s note.3 I am going to beg Mrs. Hooker to have the great kindness to send me here two answers from you: (1) address where I can get best paper for drying plants for Henrietta4 (2) what must I call the simple microscope made by Ross?? (where does he live?) which you recommend for young Surgeons, & about what does it cost?—5

The remainder of this letter read at any time. You stated at Linn. Soc. that different sets of seedling Cinchona grew at very different rate, & from my Primula case you attributed it probably to two sorts of pollen;6 I confess I thought you rash, but I now believe you were quite right. I find the yellow & crimson anthers of same flower in the Melastomatous Heterocentron roseum, have different powers; the yellow producing on the same plant thrice as many seeds as the crimson anthers;7 I got my neighbours most skilful gardener8 to sow both kinds of seeds & yesterday he came to me & said it is a most extraordinary thing that though both lots have been treated exactly alike one lot all remain dwarfs, & the other lot are all rising high up. The dwarfs were produced by the pollen of the crimson anthers.9 In Monochætum ensiferum the facts are more complex & still more strange; as the age & position of the pistil comes into play in relation to the two kinds of pollen.10 These facts seem to me so curious, that I do not scruple to ask you, (mind, when you have a little leisure) to see whether you can lend me any Melastomatad, just before flowering, with a not very small flower, & which will endure for a short time a greenhouse or sitting room; when fertilised & watched, I could send it to Mr Turnbulls11 to a cool Stove to mature seed. I fully believe the case is worth investigation.

Farewell, my dear old fellow. Yours affect. | C. Darwin

You will not have time at present to read my orchid book:12 I never before felt half so doubtful about anything which I published: when you read it, do not fear “punishing” me, if I deserve it. Adios.— I am come here to rest, which I much want.—13

Whenever you have ocasion to write pray tell me whether you have Rhododendrum Boothii from Bhootan with a smallish yellow flower & pistil bent the wrong way; if so I would ask Oliver to look for nectary, for it is an abominable error of nature, that must be corrected.— I could hardly believe my eyes, when I saw the pistil.—14


The date is established by reference to the Darwins’ stay at Leith Hill Place, home of Josiah Wedgwood III (see n. 13, below).
CD had asked Hooker to examine the stigma of Leschenaultia biloba (see letter to J. D. Hooker, 1 May [1862]), and had apparently sent him specimens at Hooker’s request (see letter from J. D. Hooker, [5 May 1862], and letter to J. D. Hooker, 9 May [1862]). Hooker’s father, William Jackson Hooker, was director of the Royal Botanic Gardens, Kew.
Frances Harriet Hooker’s letter to Emma Darwin has not been found.
Henrietta Emma Darwin.
The reference is to the optician and scientific instrument maker, Thomas Ross, whose father, Andrew Ross, had been one of the pre-eminent manufacturers of microscopes in Victorian London (Turner 1989, p. 154). Ross’s factory was at 2 and 3 Featherstone Buildings, High Holborn, London (Post Office London directory 1861). See also letter from J. D. Hooker, [17 May 1862].
Hooker’s comments may have been made either following CD’s presentation of his paper, ‘Dimorphic condition in Primula’, before the Linnean Society of London on 21 November 1861, or during the Linnean Society meeting of 3 April 1862.
The reference is apparently to the results of pollination experiments that CD carried out on Heterocentron roseum between October 1861 and January 1862. The results of these experiments, showing that crosses with pollen from the yellow anthers produced twice as much seed as those with pollen from the crimson anthers, are recorded in a note dated 3 February 1862 (DAR 205.8: 46; see also letter to George Bentham, 3 February [1862]).
The reference is probably to John Horwood, gardener to CD’s neighbour, George Henry Turnbull; Horwood had supplied CD with specimens of Heterocentron roseum and Monochaetum ensiferum (see DAR 205.8: 24 and 47). He had previously assisted CD with his study of orchids (see Correspondence vol. 9), and is acknowledged in Orchids, p. 158.
There is a note recording this observation, dated 14 May 1862, in DAR 205.8: 49. CD recorded similar observations on 30 May and 9 August 1862 (see DAR 205.8: 49–50).
CD had observed that the position of the pistil in flowers of Monochaetum ensiferum changed over time (see letters to Asa Gray, 16 February [1862] and 15 March [1862]). For CD’s attempts to understand the significance of these changes, see the dated experimental notes relating to this species in DAR 205.8: 22–43.
George Henry Turnbull (see n. 8, above).
CD had sent Hooker a presentation copy of Orchids, and had asked Hooker to inform him of any errors that he found (see Correspondence vol. 10, Appendix IV, and letter to J. D. Hooker, 9 May [1862]).
The Darwins stayed at the home of Emma’s brother, Josiah Wedgwood III, from 15 to 22 May 1862 (see Emma Darwin’s diary (DAR 242) and ‘Journal’ (Correspondence vol. 10, Appendix II)).
CD refers to Daniel Oliver. CD had previously observed that in rhododendrons, the pistils were bent so as to be in the path of insects seeking to reach the nectar (see Correspondence vol. 8, letters to J. D. Hooker, 26 April [1860] and 27 April [1860]). There is a note, dated May 1862, describing CD’s observation on R. boothii in DAR 49: 72, which is marked ‘Dichogamy’. See also the more detailed note on this subject, dated 16 May 1862, in DAR 49: 77–8. Hooker had collected many species of Rhododendron during his expedition to the Himalayas, 1848–50, and his The rhododendrons of Sikkim-Himalaya (J. D. Hooker 1849) had widened the interest of horticulturalists in using rhododendrons as garden plants. For Hooker’s reply to CD’s request, see the letter from J. D. Hooker, 23 May 1862.


Yellow anthers of Heterocentron produce on the same plant thrice as many seeds as the crimson anthers. Crimson anther seeds produce dwarf plants, others rise high up. Monochaetum ensiferum facts are still more strange. Wants to investigate the case, and asks for a plant of the Melastomataceae just before flowering.

Has JDH a Rhododendron boothii from Bhutan with pistil bent the wrong way?

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Leith Hill Place
Source of text
DAR 115: 151
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3548,” accessed on 19 February 2019,

Also published in The Correspondence of Charles Darwin, vol. 10