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Darwin Correspondence Project

From Isaac Anderson-Henry   24 April 1863

Hay Lodge, | Trinity, | Edinburgh.

April 24/63

My dear Sir

I embrace the first leisure to thank you for your very obliging note of the 20th Inst.1 and the beautifully executed likeness of yourself so kindly accorded to me.2 I have no Carte else I am so proud to possess

I was not a little struck to learn that they had got at Kew the supposed hybrid Bryanthus (erectus) wild from North America. Having a Letter from Dr Hooker by the same post which brought me yours, I have in my answer embraced the opportunity of asking him about it.3 May it not be the B. Gmelini a true north American Species, not previously introduced and noticed by D Don in Edin: Phil: Journal 17 p 160.?4 At same time there is, I must confess, a mystery about Mr Cunninghams hybrid, (B. erectus)   His nephew now in a Nursery (Messrs Lawsons) hard by here, owned to me that his uncle was not quite certain of its parentage tho he believed it to be as given out,—viz a cross between the Rhods. Chamæcistus & a Menziesia.5 I think I mentioned to you that I was at that time at work myself attempting a mule between these same things—but I made the Rhodothamnus, and not the Menziesia the seed bearer,—& did not succeed.6 On hearing of Mr C’s cross, I inverted the X, and made Menziesia (Phyllodoce) Cærulea the female, & the R Chamæcistus the male parent which succeeded and from the seeds I raised one or two plants, which I lost early by the incursion of a snail. I then held that those in that order must have been the parents of the B. erectus. I have this year wrought the R. Chamæcistus on both, vizt on the Phyllodoce (M) Cærulea and M. empetriformis. I am not sure that any one of the Xs on M. Cærulea has taken—but all of those (4 or 5) on the empetriformis seem to have taken, & the pods are already unmistakeably swollen with the ripening seeds. This looks like confirmation of Mr C’s selection and success. And I need not say that long experience (20 years of it) has made me most careful by previous emasculation, &c, to secure against the interference of insects

Many many thanks for your most interesting Paper on the Linum family.7 I wrought upon that tribe last year, and have, if true, one cross from it—vizt. L. rubrum Grandiflorum (annual) crossed on L. album, a perennial, the plants from which are now six inches high. But I was grievously puzzled & perplexed by the varying forms of the sexual organs on the different species,— in so much that I began to conclude from these and the want of success that Botanists had erred in the arrangement of the tribe, & that several species must be removed to another family. I wrought on a great many sps.— L. trigynum (with its 3 styles) L. flavum, L. perenne, L Corymbiflorum, yellow (a most obstinate thing which bore seed in no form), L. album a fine large white flowered perennial, L. flavum (which likewise bore no seed) and L. rubrum Grandiflorum— The L. trigynum let alone was the best seed bearer of them all; but I accomplished no certain cross upon it. I have the whole in array for further operations this year, & with the light you have thrown upon the genus, I will now resume my experiments with fresh avidity8

If I remember aright, I was perplexed in the same way in the Phlox family; with these short and long stamens—and perhaps it was from this cause & not falling on the corresponding styles, that I failed often, where I had reckoned success certain

And there are other tribes with which I have been grievously baffled, tho I cannot now recall them, for the like reason

Your discovery I am persuaded involves a law which pervades innumerable races.9 It is akin to Newtons discovery of the law of Gravitation10   The more I think of it, the more I am astounded by its importance & the further discoveries to which it will lead. I had long believed that different results were produceable by the different pairs of anthers on plants having these organs of unequal length,—e.g. the Geraniaceæ, the Rhodoraceæ &c &c   Now, we must have regard to the styles—the length of them—tho I incline to the belief, that this law may be found limited mainly to tribes having the anthers all of equal lengths.

Believe me; you are yet but on the threshold,—tho you have unlocked the portal in which the greatest merit lies.

If I can aid in any way do kindly suggest to me   Mean time I remain | very faithfully yours | Is. anderson Henry

I am keeping mind the experiment on the top flower of the Geranium11

Many thanks for your suggestion as to Bates Travels—12 I devour all these Books of Travels whose writers speak at all intelligibly of Natural history   But how few of them do?

P.S. On looking again, I find appearance of one pod of Menziesia Cærulea X Rhod. Chamæcistus having taken

We have formed a Microscopic Club here limited to 15 among whom are a good many Professors of the University. Dr Greville is our Chairman13   Will the knowledge of the microscope aid me much in any experiments you would suggest?

Charles Darwin Esqr F.R.S. &c &c

CD annotations

3.8 L. trigynum … Corymbiflorum,] cross in margin, ink
4.1 I was … stamens— 4.2] cross in margin, ink
6.7 I incline … lengths. 6.8] cross in margin, ink
7.1 Believe … lies. 7.2] scored ink
12.2 Will … suggest? 12.3] cross in margin, ink


The letter to Anderson-Henry has not been found; it was a response to Anderson-Henry’s letter of 17 April 1863.
In his letter of 17 April 1863, Anderson-Henry sent his own photograph and requested one from CD.
The reference is to Joseph Dalton Hooker, assistant director at the Royal Botanic Gardens, Kew (R. Desmond 1994). The supposed hybrid Bryanthus erectus was discussed in the letters from Isaac Anderson-Henry, 26–7 January 1863 and 17 April 1863. See also letter to Isaac Anderson-Henry, 2 February [1863] and n. 8.
Bryanthus gmelini was described by the botanist David Don (Don 1834); it is native to north-eastern Asia.
The references are to James Cunningham and to Peter Lawson & Sons, a firm with several nurseries in Edinburgh (Post Office Edinburgh and Leith directory 1863–4). Cunningham’s nephew has not been identified. Cunningham was reported to have obtained Bryanthus erectus by crossing Phyllodoce (Menziesia) caerulea with Rhodothamnus chamaecistus (Gardeners’ Chronicle and Agricultural Gazette, 1 November 1851, p. 695).
See letters from Isaac Anderson-Henry, 26–7 January 1863, and 31 January 1863 and n. 4.
‘Two forms in species of Linum’ was read before the Linnean Society on 5 February 1863. Anderson-Henry’s name appeared on CD’s presentation list for the Linum paper (see Correspondence vol. 11, Appendix IV).
The crossing experiments with Linum were discussed in Anderson-Henry 1867b.
In ‘Two forms in species of Linum’, CD described dimorphism in some flax species, and demonstrated that each form was often far more fertile when crossed with another form, than when pollinated with own-form pollen.
Isaac Newton advanced his theory of gravitation in 1687 (DSB).
In his letter to Anderson-Henry of 20 January [1863], CD discussed his work with the central peloric flowers of Pelargonium, a genus of Geraniaceae. Anderson-Henry wrote that he would test the fertility of such flowers (see letter from Isaac Anderson-Henry, 26–7 January 1863).
Bates 1863; see CD’s annotation to letter from Isaac Anderson-Henry, 17 April 1863.
Robert Kaye Greville was a botanist and entomologist, and honorary secretary of the Botanical Society of Edinburgh (DNB, Medical directory 1863). For the proliferation of Victorian microscope clubs and societies, see S. V. F. Butler et al. 1986, pp. 7–9, 11–16.


Bryanthus erectus, said by [D. D.?] Cunningham to be a hybrid, has been found wild in North America.

Letter details

Letter no.
Isaac (Henry, Isaac Anderson) Anderson-Henry
Charles Robert Darwin
Sent from
Source of text
DAR 159: 65
Physical description
7pp †

Please cite as

Darwin Correspondence Project, “Letter no. 4126,” accessed on 19 April 2019,

Also published in The Correspondence of Charles Darwin, vol. 11