To J. D. Hooker 15 March [1857]1
Down Bromley Kent
My dear Hooker
I have thought you would like to see enclosed which please return.2 & I shd. have sent it earlier, but I sent the last page to H. C. Watson for advice.—3 The pencil scores mean nothing.—
I asked A. Gray whether he cd. tell me about Trees in U. States; & I told him that I had expected they wd have sexes tending to be separate from theoretical notions, & I told him result for Britain & N. Zealand from you.—4
I have been thinking over your casual remarks at the Club, versus “accidental” dispersal, in contradistinction to dispersal over land more or less continuous;5 & your remarks do not quite come up to my wishes; for I want to hear whether plants offer any positive testimony in favour of continuous land.— Your remarks were that the dispersal & more especially non-dispersal could not be accounted for by “accidental” means; which of course I must agree to & can say only that we are quite ignorant of means of trans-oceanic transport. But then all these arguments seem to me to tell equally against “continuous more or less” land; & you must say that some were created since separation on mainlands, & some extinct since on island.— Between these excuses on both sides, there seems not much to choose, but I prefer my answer to yours.—6
The same remark, seems to me applicable to your observation on the commonest species not having been transported; for it seems bold hypothesis to suppose that the commonest have been generally last created on the mainland or soonest extinguished on the island.— But I shd. like to hear whether you are prepared on reflexion to uphold this doctrine of the commonest being least widely disseminated on outlying islds.— I know it holds in New Zealand & feebly owing to distance in Tristan d’Acunha., but generally I shd. have taken from De Candolle a different impression:—7 I am referring only to identical species in these remarks.—
What I shd. call positive evidence would be if proportions of Families had been exactly same on island with mainland.— If all plants were common to some mainland & island (as in your Raoul Isd.)8 more especially if some other main-land was nearer.— If soundings concurred with any great predominance of species from any country—or any other such argument of which I know nothing.
Do not answer me, without you feel inclined, but keep this part of subject before your mind for some future essay. I have written at this length that you may see, what I for one shd. like to see discussed. But I will stop for I could go on prosing for another hour.—
I hope to get a feeble ray of light on Protean genera from A. Gray: how infinitely kind he has been to me.
I have just heard from H. C. Watson with whom I have been corresponding on protean genera; & I find I shall have to send back to Gray the latter half—of his letter,9 which I daresay you wd. not care to see.
So adios | Ever yours | C. Darwin March 15th.—
Footnotes
Bibliography
Candolle, Alphonse de. 1855. Géographie botanique raisonnée ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle. 2 vols. Paris: Victor Mason. Geneva: J. Kessmann.
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.
Summary
Separation of sexes in trees [U. S.].
Do plants offer positive evidence for "continuous land" theory?
Protean genera.
Letter details
- Letter no.
- DCP-LETT-2066
- From
- Charles Robert Darwin
- To
- Joseph Dalton Hooker
- Sent from
- Down
- Source of text
- DAR 114: 193
- Physical description
- ALS 6pp
Please cite as
Darwin Correspondence Project, “Letter no. 2066,” accessed on 19 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-2066.xml
Also published in The Correspondence of Charles Darwin, vol. 6