To J. D. Hooker   9 December [1857]1

Down Bromley Kent

Dec. 9th

My dear Hooker

I am infinitely obliged for your opinion on the results from D. C. If you can spare 2 or 3 more vols. of D. C. & can send them by enclosed address on 16th, I will most gladly have them worked out: please choose whatever vols. you think best to try the result.2

But I cannot agree with you for my object, that general monographs are best: (1st) I presume the varieties wd. be best known in small country like ours; 2d. a very large genus might have very few species in many separate countries & then according to my doctrine, on average it wd not be a numerically increasing or varying genus. Again a genus, though small for its order in a monograph, might be large in any one country, & then it ought to be there on average an increasing or varying genus. For such & other reasons, I rely more on local floras, but I am very anxious to see how rule goes in whole orders. Generally perhaps universally I shd have expected, owing to great diffusion of plants, that same rule would hold in all cases, viz in local & mundane flora.—

I will see how Labiatæ are in Ledebour, Asa Gray & Koch;3 & I will divide the species in D. C. into two more equal bodies.—

I quite see that this case is a great blow to me; but please, observe, I now rest on pretty large induction. Britain by 3 separate & very different men (I long to try Bentham),4 France Germany. N. Italy, Roumelia, Ledebour (tried by separate volumes, & as whole) United States Canary Isd., India,, & N. Zealand.— All tell one story.—

Please thank Mr Bentham about Silene,5 & thanks for all other points in your letter.—

I have written to Müller & Moore.—6

You speak of my having “so few aids”; why you yourself for years & years have aided me in innumerable ways, lending me books, giving me endless facts, giving me your invaluable opinion & advise on all sorts of subjects, & more than all, your kindest sympathy.

My dear Hooker | Yours affectionately | C. Darwin

2
CD eventually used six volumes of Candolle and Candolle 1824–73 for his calculations. They covered the orders Leguminosae, Rosaceae, Borragineae, Scrophulariaceae, Acanthaceae, Verbenaceae, Labiatae, Solanaceae, Proteaceae, and Polygonaceae (Natural selection, pp. 153–4).
3
Ledebour 1842–53, A. Gray 1856a, and Koch 1843–4.
4
CD was not able to incorporate data from Bentham 1858 into his table on the number of species and varieties in large and small genera (see Natural selection, pp. 149, 152). By the time Bentham 1858 was published, CD was busy writing Origin.
6
See letter to Ferdinand Jakob Heinrich von Mueller, 8 December [1857]. CD’s letter to Charles Moore, director of the botanic gardens at Sydney, Australia, has not been located.

Manuscript Alterations and Comments

2.4 a numerically] interl
2.4 genus] above del ‘species’
2.6 on average] interl
2.8 perhaps universally] interl
2.9 same] over illeg
2.9 hold] after del illeg
4.1 observe] after del ‘I’
4.4 United States] interl

Please cite as “DCP-LETT-2182,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-2182