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Darwin Correspondence Project

To J. D. Hooker   6 October [1862]

Down Bromley Kent

Oct 6th.

My dear Hooker.

Sincere thanks for opinion on Drosera, which will be of real use as guide & your note shall be put in the Drosera Portfolios.1 I do not know whether others know the feeling, but if I work for a time hard on any subject, I become absolutely incapable of judging of its value.

I enclose 2 Queries, which you can answer by a word.

But here is a rather more bothersome affair, on which I am really ashamed to trouble Oliver without your aid.2 If you will ask Oliver, I think he will tell you I have got a real odd case in Lythrum.3 It interests me extremely; & seems to me the strongest case of propagation recorded amongst plants or animals, viz a necessary triple alliance between 3 hermaphrodites.— I feel sure I can now prove the truth of case, from a multitude of crosses made this summer.—4

Now Oliver at my request sent me a set of buds of L. Graefferi; but I most stupidly forgot that I shd. require open flowers (i.e. with petals expanded) to establish comparison with L. salicaria: the buds answered capitally & I got pollen from all the anthers; but I cannot complete case without open flowers.—5 I do not care for localities, if I have single flower from 6 or 7 distinct plants. This species is trimorphic like L. salicaria. Some flowers of L. thymifolia would be extraordinarily interesting to me, as Vaucher says it is dimorphic;6 & I am most curious to see how a trimorphic form passes or graduates into di-morphic. Is it very much trouble to turn to these plants in the Herbarium?— No case has so much interested me. & I shall write paper for Linnean.—7

I hope that you may have gone to Cambridge & read your Wellwitschia paper;8 it does seem a most grand case to connect two such groups; & I presume you will leave the Gymnosperms, which I am rather glad of.— Oh for your chart of vegetable orders to hang up & study!— I failed in going to Cambridge from another accursed attack of Eczema. I shd. so much like to pay you a visit of an hour or two at Kew, that I must try; but I get to dread more & more fatigue. I grieve to hear about Miss Henslow.9

Pray thank Oliver for his clear & favourable notice of my Orchid Book.10 I have been going through the Bibliography & picking out references: by Heavens what labour; I shd. not have thought any mortal man could have done it.11

Farewell. This is a horridly dull & troublesome letter. Farewell | Yours affectly | C. Darwin

Queries, which you can answer by a word on this paper.—

(1) In two forms of Linum perenne, I find in one, the stigmatic surface faces the axis of flower; in the other form twist of style the five stigmas face the circumference of flower. Is this a character of any importance? For instance, if you found this difference in a form, which you doubted whether to rank as a species or variety, would this difference decide you?12

(2) Shall I return the 3 Melastomatads by Railway; must I mark by any Railway?

(N.B They came here much broken, & I fear will suffer in their return.)13

P.S. Here is a fact which may possibly interest you. In a field here I find many Verbascum thapsus & lychnitis; & lots of varieties making an almost perfect series between these two distinct forms. I am sure many species have been run together on less perfect evidence. But lo & behold every one of these intermediate forms are absolutely sterile! & no doubt are natural hybrids. I found 33 of these hybrids in one field!!14


Hooker’s response to CD’s letter of 26 September [1862] has not been found. CD’s work on the insectivorous plant Drosera rotundifolia was eventually published in 1875 in his book Insectivorous plants; the extant portfolios of notes on the subject are in DAR 54–61.
Daniel Oliver was librarian and assistant in the herbarium at the Royal Botanic Gardens, Kew.
There are dated notes from CD’s experiments with Lythrum salicaria during the summer of 1862 in DAR 27.2.
See letters to Daniel Oliver, 14 September [1862] and n. 3, and [17 September 1862] and n. 3.
‘Three forms of Lythrum salicaria was read before the Linnean Society of London on 16 June 1864.
Hooker was preparing a monograph on the Angolan plant Welwitschia mirabilis (J. D. Hooker 1863a), and had intended to display the plant at the 1862 meeting of the British Association for the Advancement of Science, held in Cambridge from 1 to 8 October (see letter from J. D. Hooker, 16 September 1862).
The reference is to one of Frances Harriet Hooker’s aunts, probably Anne Frances Henslow (see letter from J. D. Hooker, 20 August 1862 and n. 4).
CD had suggested to Oliver that he should write a review of Orchids for the Natural History Review (see letter to Daniel Oliver, 24 July [1862], and letter from Daniel Oliver, 28 July 1862). In the event, Hooker wrote the review ([J. D. Hooker] 1862d; see letter from J. D. Hooker, 7 November 1862).
CD refers to the botanical bibliography in the latest number of the Natural History Review, apparently compiled by Oliver, who was an editor of the journal ([Oliver] 1862d). CD’s annotated copies of the Natural History Review are in the Darwin Library–CUL.
Having discovered in 1861 that certain species of Linum were dimorphic, CD carried out crossing experiments in the summer of 1862 on L. perenne and L. grandiflorum; the results from these experiments are given in ‘Two forms in species of Linum, which was read before the Linnean Society on 5 February 1863. In the paper (pp. 75, 78–80), CD noted the torsion of the style in the long-styled form of L. perenne, and discussed its importance in effecting cross-pollination (Collected papers 2: 98, 100–3). CD’s query apparently reflects his interest in the parallels between the sterility of a dimorphic plant with its own-form pollen and interspecific sterility (see, for instance, letter to J. D. Hooker, 22 [August 1862] and n. 16). See also Correspondence vol. 10, Appendix VI.
The reference is probably to the three melastomaceous plants that Hooker sent from the Royal Botanic Gardens, Kew, in May 1862, for use in CD’s experiments on the possible occurrence of a novel form of dimorphism in the Melastomataceae (see letter from J. D. Hooker, [29 May 1862] and n. 3). There are notes dated 2 October 1862 in DAR 205.8: 54, which record the results of crossing experiments carried out in June and July 1862 on a specimen from Kew of the melastomaceous plant Heterocentron Mexicanum.
Having transplanted a wild specimen of Verbascum into his garden in order to repeat the hybridisation experiments of Karl Friedrich von Gärtner, CD had been unable to obtain fertile seed-pods from the plant (see letter to W. E. Darwin, 4 [July 1862] and n. 4). In consequence, he searched the field in Cudham Valley, near Down House, from which the plant had been removed, and obtained the results reported here. CD’s notes on this subject, dated 4, 6, and 16 October 1862, are in DAR 108: 3–4; he reported his observations in ‘Specific difference in Primula, pp. 451–4.


Collected papers: The collected papers of Charles Darwin. Edited by Paul H. Barrett. 2 vols. Chicago and London: University of Chicago Press. 1977.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

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

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.

‘Specific difference in Primula’: On the specific difference between Primula veris, Brit. Fl. (var. officinalis of Linn.), P. vulgaris, Brit. Fl. (var. acaulis, Linn.), and P. elatior, Jacq.; and on the hybrid nature of the common oxlip. With supplementary remarks on naturally produced hybrids in the genus Verbascum. By Charles Darwin. [Read 19 March 1868.] Journal of the Linnean Society (Botany) 10 (1869): 437–54.

‘Three forms of Lythrum salicaria’: On the sexual relations of the three forms of Lythrum salicaria. By Charles Darwin. [Read 16 June 1864.] Journal of the Linnean Society (Botany) 8 (1865): 169–96. [Collected papers 2: 106–31.]

‘Two forms in species of Linum’: On the existence of two forms, and on their reciprocal sexual relation, in several species of the genus Linum. By Charles Darwin. [Read 5 February 1863.] Journal of the Proceedings of the Linnean Society (Botany) 7 (1864): 69–83. [Collected papers 2: 93–105.]

Vaucher, Jean Pierre Etienne. 1841. Histoire physiologique des plantes d’Europe ou exposition des phénomènes qu’elles présentent dans les diverses périodes de leur développement. 4 vols. Paris: Marc Aurel Frères.


Thanks for opinion on Drosera. After working for a time on a subject he is absolutely incapable of judging its value.

Has found a case in Lythrum of a necessary triple alliance between three hermaphrodites; the strangest case of propagation recorded among plants or animals.

Asks for L. thymifolia to see how a trimorphic form passes or graduates into dimorphic.

Questions JDH on Linum perenne.

Has found 33 hybrids in one field between Verbascum thapsus and V. lychnitis. The perfect series of varieties would have justified running the species together, but every one of the intermediate forms is sterile.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 115: 164
Physical description
ALS 7pp

Please cite as

Darwin Correspondence Project, “Letter no. 3753,” accessed on 15 July 2024,

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