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Darwin Correspondence Project

To J. D. Hooker   15 November [1854]

Down Farnborough Kent

Nov. 15

My dear Hooker

Thank you for your last note with news of Richmond Hill, which I have been studying on the map. I have been trying to do a little about aberrants, but before I tell you, (thinking that you might possibly like to hear) I must beg you to thank Mr. Bentham particularly for the Historical notes,1 which by chance I had see referred to but 2 days before, & wished much to see in regard to Figs.—2

In Shoenherrs Catalogue of Curculionidum,3 the 6717 species are on average 10.17 to genus. Waterhouse, (who knows the group well) (& who has published on fewness of species in aberrant genera)4 has given me a list of 62 aberrant genera,5 & these have on average 7.6 species; & if 1 single genus be removed (& which I cannot yet believe ought to be considered aberrant) then the 61 aberrant genera wd. have only 4.91 species on average.— I tested these results in another way. I found in Schoenherr 9 Families including only 11 genera, & these genera (9 of which were in Waterhouses list) I found included only 3.36 species on an average.6

This last result led me to Lindleys Vegetable Kingdom7 in which I find (excluding Thallogens & Acrogens) that the genera include each 10.46 species (how near by chance to the Curculionidæ) & I find 21 orders including single genera, & these 21 genera have on average 7.95 species; but if Lindley is right that Erythroxylon (with its 75 species) ought to be amongst the Malpighiads, then the average wd. be only 4.6 per genus.

But here comes, as it appears to me, an odd thing, (—I hope I shall not quite weary you out,)—there are 29 other orders, each with 2 genera & these 58 genera have on average 15.07 species: this great number being owing to the 10 genera in the 1Smilaceæ, 2Salicaceæ (with 220 spec.s) 3Begoniaceæ, 4Balsaminaceæ 5Grossulariaceæ, without which, the remaining 48 genera, wd have on average only 5.91 species.—

This case of the orders with only 2 genera, the genera, notwithstanding having 15.07 species each, seems to me very perplexing, & upsets almost the conclusion deducible from the orders with single genera.

I have gone higher, & tested the Alliances8 with 1, 2, & 3 Orders, & in these cases, I find both the genera few in each alliance, & the species, less than average of whole kingdom, in each genus.—

All this has amused me,9 but I daresay you will have a good sneer at me, & tell me to stick to my Barnacles. By the way you agree with me that sometimes one gets despondent, for instance when theory & facts will not harmonise; but what appears to me even worse, & makes me despair, is, when I see from the same great class of facts, men, like Barrande deduce conclusions, such as his Colonies10 & his agreement with E. de Beaumonts lines of Elevation,11 or such men as Forbes with his Polarity;12 —I have not a doubt that before many months are over I shall be longing for the most dishonest species as being more honest than the honestest theories.— One remark more, if you feel any interest, or can get anyone else to feel any interest on the aberrant genera question, I shd. think the most interesting way wd be to take aberrant genera in any great natural Family, & test the average number by the number of species to the genera in that Family.—

How I wish we lived near each other; I shd. so like a talk with you on geograph. distribution, taken in its greatest features; I have been trying from land productions to take a very general view of world, & I shd. so like to see how far it agrees with plants.

But adios for the present. Ever your’s very truly. C. Darwin

Comfort has got the place. many thanks to you & Mrs Hooker.—13


Bentham 1855. CD’s annotated copy is in the Darwin Pamphlet Collection–CUL. It is inscribed ‘Charles Darwin Esq from the Author’, under which Hooker has added ‘George Bentham JDH’.
The Gardeners’ Chronicle and Agricultural Gazette, no. 45, 11 November 1854, pp. 727–8, carried a short extract from Bentham 1855 describing Antonio Targioni Tozzetti’s view that the garden fig (Ficus carica) had often been reared from the wild fig (the Caprificus), supposedly an entirely different genus.
Waterhouse 1845, p. 19 n. There is an annotated copy in the Darwin Library–CUL. See Correspondence vol. 3, letter to J. D. Hooker, 31 March [1844], for CD’s discussion of Waterhouse’s views.
See letter from G. R. Waterhouse, 11 November 1854, n. 2, for CD’s purpose in studying aberrant genera and the number of species.
See CD’s calculations and tables in DAR 205.9 (iii): 288–303.
Lindley 1846, although in his notes on this work (DAR 205.9 (iii): 305–10) CD incorrectly referred to it as published in 1845. CD also used the third edition (Lindley 1853).
John Lindley used the term ‘Alliances’ to denote minor groups within taxonomic classes ‘whose common characters are also more extensive than those of Natural Orders, and under which the Natural Orders are themselves assembled’ (Lindley 1853, p. xii). CD’s calculations are in DAR 205.9 (iii): 307.
At the end of his calculations on Lindley 1846 (DAR 205.9 (iii): 310), CD wrote: A creationist might say, the fact of aberrance shows that they differ from common forms, ie forms adapted to commonest circumstances, & therefore it is self-evident they wd. not be likely to have many species created on such type. Quite sufficient explanation. *But is is necessary for me to account for the fewness of species, after having shown such to be the case [added]. To these notes CD added in pencil: ‘Hard to apply this doctrine to Earwig or Ornithorhynchus’.
Joachim Barrande’s term for groups of more recent fossil forms found in older formations. He attributed their dislocation to migration from locations in which they had already appeared rather than to disturbances in the formations. See Barrande 1852–1911.
Jean Baptiste Armand Louis Léonce élie de Beaumont’s controversial theory that the directions of the lines of the earth’s mountain systems formed a geometrical pattern.


Barrande, Joachim, et al. 1852–1911. Systême silurien du centre de la Bohême. 8 parts in 28 vols. Prague: the author.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Lindley, John. 1846b. The vegetable kingdom. London: the author.

Lindley, John. 1853. The vegetable kingdom; or, the structure, classification, and uses of plants, illustrated upon the natural system. 3d edition with corrections and additional genera. London: Bradbury & Evans.


Calculating small number of species in aberrant genera of insects and plants.

Joachim Barrande’s "Colonies", Élie de Beaumont’s "lines of Elevation", Forbes’s "Polarity" make CD despair, as these theories lead to conclusions opposite to CD’s from the same classes of facts.

Letter details

Letter no.
Charles Robert Darwin
Joseph Dalton Hooker
Sent from
Source of text
DAR 114: 156
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 1601,” accessed on 18 January 2022,

Also published in The Correspondence of Charles Darwin, vol. 5