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Darwin Correspondence Project

To J. D. Hooker   30 October [1873]1


Oct 30th

My dear Hooker

How good you have been to send me so splendid a lot of leaves.— I have worked many hours at them, & made rough notes on all.2 I have resolved it wd. be waste of time to work longer at them, as some were slightly withered & this may affect the bloom, & it is better to work deliberately on a few living plants.3 But my notes will be of the greatest service when I get plants from Rollisson & Co;4 & if results prove interesting, I may ask you for 2 or 3 living species. You will not conceive such ignorance as mine, yet I cannot distinguish all the Eucalypti from the Acacias. Therefore I have returned by this post the specs. in a tin box, each with a number attached; & if you will take them out in any order write the number down & put opposite E for Eucalyptus & A for Acacia, (I suppose these are sub-genera, but I can say genera in large sense.)5 & the specimens will be ten-fold more valuable to me.— But if you chance to know specific name, please add them. About the specimens numbered 2. 4. 7. 10. 14. 22. 24. 25. 27. & 31. I have made fuller notes, (i.e the temp. at which bloom removed &c &c) & the specific names in their case would probably be more useful to me; but do not go & hunt them up. Perhaps you would roll the whole lot up in brown paper & return them; & then if I find the subject promises well, I could send any one or two about which I felt particular interest for name, or for living specimen.— My notion is that perhaps vertical position serves as protection against rain soaking the leaf, owing to the bloom, when present, being easily removed; it may turn out all a hallucination: it is not, however, I think so with Mimosa pudica & some others.6

The branches of Acacia farnesiana7 arrived withered & leaflets closed, still I could see enough to make me wish much to examine the plant, if you think it can be sent safely. If sent please have marked conspicuously on Label “To be sent off immediately in a Fly.” Remember address is “Orpington St. S.E. Railway.”

I will write again soon.—

I have thought of several rather troublesome experiments for Drosophyllum, so can you lend me a plant, I will return it in a fortnight.—8

The secreting & absorbing glands are the same in Drosera & Dionæa, but apparently not so in Drosophyllum.9

We go to Henrietta’s House on Friday week & stay there a week—10 I am knocked up with my work.—

Yours affect | C. Darwin

I shall be so glad for seeds of Lathyrus nissolia11

P.S. I have just recd the enclosed from Lyell, to be forwarded to you, & to be returned to him. Mr Wood’s remarks are interesting, though I hardly agree with one of them.12

It wd be a gt anomaly (tho’ such do occur) if a new & strongly marked variety transmitted its characters, without selection during at least 2 or 3 generations. It is likely enough in the case of those vars of apples such as Hawthorndeans which do transmit their characters, that they have gone through this process.

With respect to extinction, Mr Wood has overlooked or disregarded what I have said on rarity preceding extinction.13 It wd be easy to specify certain cetaceans which are very rare; & I suppose Mr Wood wd not be much astonished at this fact; of rarity or if he wd, there is cause in every Family for his astonishment.

The competition of better adapted forms seems to me a sufficient explanation; & I shd be unwilling to admit sterility without at least some direct evidence. I was at first much surprized at Mr Wood’s statement about the sterility of seedling apples; but I now think without sufficient cause. Apples, like so many other plants, have been rendered somewhat sterile (& the fruit consequently enlarged) thro’ changed conditions, & they apparently have transmitted this sterility.—

I have lately had a good instance of such transmission: in a lot of common Convolvulus (Ipomœa purpurea) one plant appeared which was very sterile (& this is a rare circumstance) & a second, slightly sterile. I self-fertilized them & raised seedlings this year; & the sterility has been transmitted to both lots in nearly the same relative degrees, but not equal to that of their parents.14 If you think this P.S. worth sending to Lyell, pray do so, but not otherwise.

C. Darwin


The year is established by the relationship between this letter and the letter from J. D. Hooker, 29 October 1873.
Hooker had sent CD sprigs of Acacia and Eucalyptus species (see letter from J. D. Hooker, 29 October 1873). CD’s notes have not been found.
CD’s notes on the bloom of leaves and fruit are in DAR 66 and 68; he did not publish on the subject.
CD had asked the nurseryman George Rollisson for a specimen of Desmodium (see letter to J. D. Hooker, 18 October [1873]).
The genus Acacia is now often split into five related genera: Acacia (mostly limited to Australian species), Vachellia, Senegalia, Acaciella, and Mariosousa (see Bouchenak-Khelladi et al. 2010). The genus Eucalyptus is now split into Eucalyptus, Corymbia, and Angophora (all three being known as eucalypts).
CD discussed Mimosa pudica in Movement in plants, but did not discuss its bloom.
Acacia farnesiana is now Vachellia farnesiana.
Drosophyllum lusitanicum, the Portuguese sundew or dewy pine, is an insectivorous plant.
In Insectivorous plants, pp. 6, 288, 333–4, CD concluded that the glands of Drosera rotundifolia (the common or round-leaved sundew) and Dionaea muscipula (the Venus fly trap) could both secrete and absorb, but in Drosophyllum lusitanicum, some of the glands did not secrete spontaneously.
CD stayed at the house of his daughter Henrietta Emma Litchfield, in Bryanston Street, London, from Saturday 8 to Tuesday 18 November 1873 (CD’s ‘Journal’ (Appendix II).
On Lathyrus nissolia, the grass vetchling, see the letter to Francis Darwin, 23 October [1873] and n. 2.
In Origin 6th ed., p. 85, CD noted that rarity was a precursor to extinction.
CD discussed the impaired fertility of self-fertilised Ipomoea purpurea (common morning-glory) in Cross and self fertilisation, pp. 57–9. CD’s notes on these two plants are in DAR 77: 44. CD had studied how different conditions affected the degree of self-fertility in some species, notably Eschscholzia californica; see, for example, Correspondence vol. 17, 2d enclosure to letter to Fritz Müller, 1 December [1869]).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 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.

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

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Origin 6th ed.: The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 6th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1872.


Thanks for leaves. His notes on them will be of greatest service.

He cannot distinguish some Eucalypti from Acacia. Sends specimens, with numbers, for JDH to name.

Acacia farnesiana branches arrived withered, but saw enough to make him wish to examine the plant.

Has thought of some troublesome experiments for Drosophyllum.

Encloses remarks [missing] by Searles Wood, with which CD disagrees, about a new and strongly marked variety transmitting its characters.

The competition of better adapted forms seems to CD a sufficient explanation [for extinction].

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 95: 286–9
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9117,” accessed on 23 January 2022,

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