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Darwin Correspondence Project

To J. D. Hooker   11 March [1858]

Down Bromley Kent

March 11th

My dear Hooker

I have been thinking over your note of this morning, which like all your others is of real value to me.— I quite agree with observation on small local genera not varying & mundane ones varying; but this instead of an objection strikes me as rather the very point, which I want to show by my tables.

But I will not discuss the whole subject here; indeed I am trying,as far as able, not to settle my conviction till all my results are finally worked out; when, if you will let me, I will have my M.S. fairly copied out, & sent to you.—

I really cannot at present doubt that for my theoretical object that local Floras are the best; my object being to see whether varieties are not incipient species.—1 Perhaps you will see my point of view, by taking a strong case; viz Marsupialia might well be an increasing group in Australia & a diminishing one when put into competition with Placentalia in S. America; if I lumped them, the results would be confounded & false for both sides.—

Of course I do not suppose with groups of plants so widely extended as they are, that there ever shd. be such difference, as there might be in case of Mammals. Therefore I agree that orders in a Prodromus not obeying my rule as with Labiatæ & Verbenaceæ is a serious objection; though not nearly so fatal, in my opinion, if in a local Flora.—2 I was led to all this work by a remark of Fries, that the species in large genera, were more closely related to each other than in small genera;3 & I thought if this were so, seeing that varieties & species are so hardly distinguishable, I concluded that I shd. find more varieties in the large genera than in the small: but at first, seeing the many causes of doubt, I certainly did not expect to find more than three-fourths of the Floras, yielding the result, which they have.— But I will not go on; as someday I hope you will read my short discussion on whole subject.—

You have done me infinite service, whatever opinion I come to, in drawing my attention to at least the possibility or the probability of Botanists recording more varieties in the large than in the small genera.—4 It will be hard work for me to be candid in coming to my conclusion.—

Ever yours most truly | C. Darwin

I shall be several weeks at my present job.5

The work has been turning out badly for me this morning & I am sick at heart & oh my God how I do hate species & varieties.

P.S.6 I see that I had not understood your figures— They are quite sufficent, (so I do not care for Book) to show how hostile the result is—7 But I look at this as too small an order as any good test; I find to make Balance such as I have always later, there wd be only 4 genera on one side & one of these gigantic; I very well know how you will sneer at this wriggling out— C. D.

I shall of course allude to your result on Urticeæ8

Footnotes

CD gave his reasons for preferring local floras in Natural selection, pp. 155–9.
CD’s calculations on Labiatae and Verbenaceae had not given the same results as other calculations drawn from local floras and individual volumes of Candolle and Candolle 1824–73. See letter to J. D. Hooker, 9 February [1858]. CD commented on this problem in Natural selection, p. 158.
CD quoted from Fries 1850, p. 188, in Natural selection, pp. 146–7. CD’s notes on Fries 1850 are in DAR 73: 118.
See letters to Asa Gray, 21 February [1858], and to C. C. Babington, 22 February [1858], and letter from H. C. Watson, 23 February [1858].
An entry in CD’s ‘Journal’, dated 14 April 1858, reads: ‘Discussion on large genera & small & on Divergence & correcting Ch. 6.’ (‘Journal’; Appendix II).
Although the postscript is on a separate piece of paper and written in pencil, it is clearly related to this letter.
CD refers to Hooker’s calculations on Weddell 1856 (see letter to J. D. Hooker, 10 [March 1858]).
Weddell 1856 is a monograph on the Urticeae or Urticaceae.

Bibliography

Candolle, Augustin Pyramus de and Candolle, Alphonse de. 1824–73. Prodromus systematis naturalis regni vegetabilis, sive enumeratio contracta ordinum generum specierumque plantarum huc usque cognitarum, juxta methodi naturalis normas digesta. 19 vols. Paris: Treuttel & Würtz [and others].

Fries, Elias Magnus. 1850. A monograph of the Hieracia; being an abstract of Prof. Fries’s ""Symbolæ ad Historiam Hieraciorum"". Botanical Gazette 2: 85–92, 185–8, 203–19. [Vols. 5,7]

Natural selection: Charles Darwin’s Natural selection: being the second part of his big species book written from 1856 to 1858. Edited by R. C. Stauffer. Cambridge: Cambridge University Press. 1975.

Weddell, Hugh Algernon. 1856. Monographie de la famille des Urticés. Paris.

Summary

JDH’s "objection" that small local genera do not vary and mundane ones do, is exactly CD’s point. Local floras useful to test idea that varieties are incipient species. Same genus in different countries cannot be lumped.

Letter details

Letter no.
DCP-LETT-2239
From
Charles Robert Darwin
To
Joseph Dalton Hooker
Sent from
Down
Source of text
DAR 114: 228
Physical description
9pp

Please cite as

Darwin Correspondence Project, “Letter no. 2239,” accessed on 17 November 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-2239.xml

Also published in The Correspondence of Charles Darwin, vol. 7

letter