skip to content

Darwin Correspondence Project

From J. D. Hooker   13–15 July 1858

Kew

July 13th/58.

My dear Darwin

I was at Mr Smiths of Combe Hurst1 last Sunday & met your relative Mr Mackintosh of W. Indies, who I liked very much.2

I there went deep into your Mss on variable species in big & small genera & tabulated Bentham after a fashion—but not very carefully—3 After very full deliberation I cordially concur in your view & accept it with all its consequences. Benthams book confirms you, though with modifications The larger genera I believe to be groups of more presently variable beings than the small & I think you have quite made good your point. Still I would not abandon the arguments against—for I still think that the disposition or rather the necessity of making more book varieties in large genera than in small is a very important fact.

I have also well considered Bentham’s exceptional orders, & am inclined to attribute that also partly to his idiosyncrasy—4 upon thinking well over his method of working, I have often seen that he will make rather hastily a new species in a large genus, of which a vast number of good species have recently turned up— The mental process is—“such & such a country teems with As-tragalus or Pedicularis—(which he has himself first elaborated)5 here is a new province of that country just supplied us with a lot of specimens & the chances are that heaps of them are new, & that more specimens will rather tend to prove doubtful new species to be distinct than the contrary”— It is not easy to explain to you how fully I appreciate this tendency in another person— but I am convinced it is so, & that that is the key to the Benthamian exceptional Orders—6

This does not however apply to Weddells Urticeæ which I must tabulate more carefully7 This was the case when Bentham & I did the Affghanistan & Tibet Astragali & Pediculariæ8 he pronounced many new which I thought varieties.—always saying—Oh that country is the headquarters of Astragali—you must expect heaps of novelty.

In some passages of your mss you rather underrate I think the influence of associations of this & other sorts on descriptive systematists.— Look how Babington is eternally changing his mind—or rather his opinion (for mind he has none) as to genera & species—& it is so with all of us. Brown’s Specific work on Arctic plants is execrably bad & narrow-minded & I do not doubt attributable to some passing influence of this kind.9

On rereading your mss, I find the same objections as before, viz that you overrate the extent of my opposition to your method. My great desire was to put every possible objection as strongly as I could. I did not feel myself a dissenter from or opponent to your views, so much as a non consenter to them in the present state of my knowledge, nor till you had weighed my objections, wh. I thought of greater weight than I now do.

I am still dubious about the force of your argument against large areas & whole Nat Orders, or rather, of your argument in favor of small Floras, except you confine the latter to the plants strictly belonging to that area & exclude stragglers.10 Thus Panicum in Bentham ranks as a small genus & not variable, but those very species are the most variable plants in the world, elsewhere. I am however slow at taking up arguments of that sort, one way or the other.

I have still one objection to discuss—if as many middling sized genera are decreasing as are increasing how do we know which are which.— Do the species of big genera run to varieties in decreasing as in increasing. perhaps they should do so—yet you say “it is idle to discuss this”!

July 15th. The E.I.C Examinations are cutting my time to shreds wh must account for some of the incoherency of the foregoing11

I have had more time for thinking over the subject at odd half hours & have endeavoured to grapple with the whole question. That point of the hypothetical behavior of large genera when on the decrease puzzles me.

As a corollary to your Law, Large Natural Orders should have fewer genera in proportion to species than small; i.e. fewer defineable groups— Cruciferæ, Compositae, Umbelliferæ & Grasses bear you out in this—true no end of genera are made in them but they are bad— Other natural Orders are opposed.

I think I have thought of a better reason than you give for whole N. Os being worse for your purpose than local Floras.— viz—1. that conditions do not go on varying with the area beyond a certain point:—there are limits to the combinations of Climate & soil A genus inhabiting 1000 square miles will survive such & such conditions, & under these influence form x species—all these conditions may occur in 100 miles of the said area, & adding the other 900 miles adds no more conditions. 2. Many large genera are absolutely confined to the Tropics or to temperate regions or to districts & do not stand in the same relation to one another as the mundane genera do— This I think you have expressed, but not clearly, any more than I have!

This would lead me to suggest the propriety of working one or two of your Floras by purging them of stragglers, & such plants generally as are typical of other climates & exceptional in this—of stragglers in short eg. Panicum— I think this process would intensify your results

I send the proofs from Linnæan Socy— Make any alterations you please—12 if you want 100 or 150 pages of Linn. Journal for your abstract13 I think you should have it & we could publish it as a separate supplemental number of the

Footnotes

Mr Smith has not been identified.
Robert Mackintosh was the younger brother of Frances Mackintosh Wedgwood. He had visited the Darwins at Down, 17–21 June 1858 (Emma Darwin’s diary).
See preceding letter. Hooker’s tabulation of Bentham 1858 is in DAR 100: 168. It was probably enclosed with the letter. The table is discussed by CD in his letter to J. D. Hooker, 30 [July 1858]. CD had sent his manuscript on large and small genera to Hooker in May 1858 for his comments (see letters to J. D. Hooker, 6 May [1858] and 5 July [1858]). Hooker’s comments are written on the manuscript and have been transcribed as footnotes by the editor of Natural selection, pp. 134–64. CD had previously sent Hooker a note advising him how to consider the manuscript (see the enclosure of the letter to J. D. Hooker, 10 April [1858]). This was returned with the manuscript. On the verso, Hooker wrote: ‘My pencil alterations were intended to make passages clear to myself not for corrections or hints to you so do not mind them’ (DAR 15.1 (ser. 2): 0).
George Bentham singled out two natural families of plants as ‘anomalous families’ (Bentham 1858, p. 51). These were the plumbago family (Plumbagineae), which included Statice, a worldwide genus, and the plantain family (Plantagineae), also worldwide.
Bentham had investigated Astragalus and Pedicularis in some detail. His classification of these genera were included in Royle 1839 and Bentham 1835.
Hooker had earlier warned CD to be aware of the different ways in which botanists catalogue species. CD had consequently written to several botanists to ask their opinion on the question (see letters to Asa Gray, 21 February [1858], to C. C. Babington, 22 February [1858], and letter from H. C. Watson, 23 February [1858]).
Weddell 1856. See letters to J. D. Hooker, 10 [March 1858] and 11 March [1858], and letter from J. D. Hooker, [14 March 1858].
The results of Bentham and Hooker’s work on Indian Astragalus and Pedicularis were not published until the 1870s, when Hooker’s Flora of British India (7 vols., London, 1872–97) was issued.
Brown 1824.
Hooker had always maintained that books concerned with mundane natural orders would serve CD’s purposes better than those describing localised ones. See Correspondence vol. 6, letter from J. D. Hooker, [6 December 1857], and letter to J. D. Hooker, 9 December [1857]).
In 1854, the East India Company had appointed Hooker a botanical examiner of the candidates for medical positions (L. Huxley ed. 1918, 1: 385).
The proof-sheets of Darwin and Wallace 1858 have not been located. See Appendix III for the changes made by CD.

Summary

Sends proofs [of "On the tendency of species to form varieties … ", read 1 July 1858, Collected papers 2: 3–19]. CD could publish his abstract [later the Origin] as a separate supplemental number of [Journal of the Linnean Society].

JDH has studied in detail CD’s manuscript on variable species in large and small genera and concurs with its consequences. Discusses methodological idiosyncrasies of systematists, e.g., Bentham, Robert Brown, and C. C. Babington, which complicate CD’s tabulations.

Letter details

Letter no.
DCP-LETT-2307
From
Joseph Dalton Hooker
To
Charles Robert Darwin
Sent from
Kew
Source of text
DAR 100: 116–19, 168
Physical description
table 1p

Please cite as

Darwin Correspondence Project, “Letter no. 2307,” accessed on 11 December 2018, http://www.darwinproject.ac.uk/DCP-LETT-2307

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

letter