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Darwin Correspondence Project

To Asa Gray   21 August [1862]1


Aug 21.

My dear Gray.

We are a wretched family & ought to be exterminated. We slept here to rest our poor Boy on his journey to Bournemouth, & my poor dear wife sickened with Scarlet-fever & has had it pretty sharply, but is recovering well.2 Our Boy suffered sadly from the Journey, though we took it on the advice of two Doctors. I fear he will be an invalid for months, if not years.— There is no end of trouble in this weary world.— I shall not feel safe till we are all at home together, & when that will be I know not. But it is foolish complaining.

I received a few days ago your letter of Aug. 4th, with all the interesting details on Houstonia.3 It seems a grand case. I hope that Mr Rothwick will surely publish them.4 The simple fact of two pollens in the same species, & the reciprocal action of two hermaphrodites seems to me well worth establishing; & till any first account is confirmed, nothing can be considered as established. I feel no sort of doubt after repeating my experiments on Primula; but I shall probably not publish till winter, (even if then) & so Mr. R. could first establish the case.—5

I must just recur to stamps; my little man has calculated that he will now have six stamps which no other Boy in the school has.6 Here is a triumph. Your last letter was plaistered with many coloured stamps & he long surveyed the envelope in bed with much quiet satisfaction.

I wrote you a mad letter the other day about Lythrum;7 but the case is worth some madness. Thanks for remarks about Rhexia; what you say about pollen flirting out agrees with what I have seen.— My Rhexia glandulosa seems very different, & I believe offers nothing odd.8 Heterocentron will, I suspect, turn out, as I prophecyed something marvellous like Lythrum.—9 I know almost as well as you, that systematic work is the foundation of everything; yet in your case & Hooker’s case, I perpetually feel inclined to d——n systematic work.—10 I had a note from Hooker this morning giving a pretty fair account of Mrs Hooker; but it almost seems that her heart is slightly affected.11 He tells me that he has got two wonderfully different flowers on same spike of a Vanda.

Huxley is going to bring out a very curious Book on man & monkey.—12

I can see no Honey in Melastoma;13 but secretion of Honey depends on most delicate combination of circumstances. The common Polygala will go on for many days & secret none, & then will suddenly all commence— I am scribbling away at a great rate.

Affairs seem to be getting with you more & more terrible.14 What will the end be. It seems to us here far more fearful, than it apparently does to you.

Farewell my dear Friend | C. Darwin

I shd. very much like, if time permits to hear what you think of my last chapter in Orchid-book.—15


The year is established by the reference to Emma and Leonard Darwin’s illnesses (see n. 2, below).
The Darwins had planned to take a holiday in Bournemouth to assist Leonard Darwin’s convalescence from scarlet fever (see letter from W. E. Darwin, 5 August 1862 and n. 8). According to Emma Darwin’s diary (DAR 242), CD, Emma, and Leonard travelled to Southampton on 13 August 1862; on the same date, Emma recorded that she became ill with scarlet fever.
CD refers to Joseph Trimble Rothrock, one of Gray’s students who had carried out observations and experiments for CD on the dimorphic plant Houstonia caerulea (see letter from Asa Gray, 4 August 1862). Rothrock does not appear to have published his results; however, CD included Rothrock’s findings in Forms of flowers, pp. 132, 254.
Rothrock had confirmed and expanded upon Gray’s observations of differences in the pollen from each of the two flower forms of Houstonia caerulea (see letter from Asa Gray, 4 August 1862 and n. 1). He had also demonstrated experimentally that each kind of pollen was more fertile when applied to the stigma of a flower of the other form than when applied to the stigma of a flower of the same form. This paralleled CD’s findings in Primula, published in March 1862 (‘Dimorphic condition in Primula; see General index to the Journal of the Linnean Society, p. vi). CD repeated his experiments on P. sinensis in January and February 1862, with similar results (see letter to Asa Gray, 9 August [1862] and n. 13); however, he did not publish his findings until 1869 (‘Illegitimate offspring of dimorphic and trimorphic plants’).
Since June, Gray had sent North American postage stamps for Leonard Darwin (see letters to Asa Gray, 10–20 June [1862], 23[–4] July [1862], 28 July [1862], and 9 August [1862], and letters from Asa Gray, 2–3 July 1862, 15 July [1862], and 21 July 1862).
CD suspected that plants of the melastomaceous genus Rhexia might be dimorphic, and had asked Gray to make observations for him (see letter from Asa Gray, 4 August 1862 and nn. 3–6). Having obtained a specimen of Rhexia glandulosa (a synonym of Monochaetum floribundum), CD carried out crossing experiments, the results of which he reported in his letter to Gray of 10–20 June [1862]. Detailing his observations on Rhexia Virginica in his letter to CD of 4 August 1862, Gray wrote: ‘I suppose you have examined no true Rhexia.’
In October 1861, CD had begun to investigate the occurrence of two different sets of stamens in each flower of Heterocentron roseum, those facing the petals differing in structure and colour from those facing the sepals (see Correspondence vol. 9, letter to J. D. Hooker, 17 November [1861]). Suspecting that this might be a novel form of dimorphism (see letter to George Bentham, 3 February [1862]), he carried out pollination experiments between October 1861 and January 1862, in which the crosses made with pollen from the yellow anthers produced more seed than those made with pollen from the crimson anthers. In addition, the seedlings produced from the former crosses grew much larger than those resulting from the latter (see letter to J. D. Hooker, 15 [May 1862] and nn. 7–9). On 9 August, CD again compared the two sets of seedlings, noting: ‘the bigger ones were still twice as tall; the smaller being more compact habit & more purplish leaves’ (DAR 205.8: 50). However, despite continuing to work on the family throughout 1862 and 1863, CD was not able to account for the two sets of stamens (see Cross and self fertilisation, p. 298 n., and ML 2: 292–302).
In his letter to CD of 4 August 1862, Gray commented that, since he was preparing to do systematic work, he would be unable to carry out observations and experiments for CD. For CD’s concern at the amount of time Joseph Dalton Hooker spent preparing his Genera plantarum (Bentham and Hooker 1862–83), see the letter to J. D. Hooker, 9 February [1862], and the letter to Asa Gray, 21 April [1862].
In his letter to CD of 4 August 1862, Gray mentioned that he could see no nectar in the melastomaceous plant Rhexia Virginica.
CD apparently refers to Gray’s comments in his letter to CD of 29 July 1862, on the progress of the American Civil War.
CD refers to chapter 7 of Orchids, which examined the homologies of the parts of orchid flowers, and ended with concluding remarks on natural selection and on the importance of cross-fertilisation (Orchids, pp. 286–360). See also letter to Asa Gray, 23[–4] July [1862] and n. 21.


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

Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

‘Dimorphic condition in Primula’: On the two forms, or dimorphic condition, in the species of Primula, and on their remarkable sexual relations. By Charles Darwin. [Read 21 November 1861.] Journal of the Proceedings of the Linnean Society (Botany) 6 (1862): 77–96. [Collected papers 2: 45–63.]

Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.

General index to the Journal of the Linnean Society: General index to the first twenty volumes of the Journal (Botany), and the botanical portion of the Proceedings, November 1838 to June 1886, of the Linnean Society. London: Linnean Society of London. 1888.

‘Illegitimate offspring of dimorphic and trimorphic plants’: On the character and hybrid-like nature of the offspring from the illegitimate unions of dimorphic and trimorphic plants. By Charles Darwin. [Read 20 February 1868.] Journal of the Linnean Society of London (Botany) 10 (1869): 393–437.

ML: More letters of Charles Darwin: a record of his work in a series of hitherto unpublished letters. Edited by Francis Darwin and Albert Charles Seward. 2 vols. London: John Murray. 1903.

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.


Emma and Leonard have scarlet fever.

Houstonia seems "a grand case"; J. T. Rothrock should publish his observations on the two pollens and the reciprocal action of two hermaphrodites.

Rhexia glandulosa offers nothing odd, but Heterocentron will turn out something marvellous like Lythrum.

Would like to know what AG thinks of last chapter of Orchids.

Letter details

Letter no.
Charles Robert Darwin
Asa Gray
Sent from
Source of text
Gray Herbarium of Harvard University (67)
Physical description
ALS 6pp

Please cite as

Darwin Correspondence Project, “Letter no. 3692,” accessed on 23 July 2024,

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