To William Robinson   [29 April 1866]1

6. Queen Anne St

Sunday

Dear Sir.—

I was very sorry to have missed seeing you & hope I shall be more fortunate when I may next be in London; for I return home tomorrow morning.2

I am much obliged for your obliging offer of assistance, which I will keep in mind.3 I may mention (though it is improbable that you can aid me) one point.— If you have Euryale ferox & if it produces more than one flower at a time, I wish you would cross some & fertilise some others with their own pollen, in order to see, when the seeds are counted (which I would undertake), whether the cross aids at all in increasing fertility. Properly pollen ought to be taken for the cross from a distinct plant.— The Euryale is dead at Kew, where they wd. have made the trial on a large scale for me.—4 Prof Caspary has advanced this plant as a case of self-fertilisation for many generations with unimpaired fertility.5

If you have two distinct plants of any Nymphæa, I shd. much like the above trial to be made, but the flowers which are fertilised with own pollen ought to be protected, whilst expanded from insects.—

With my thanks for your kind offer. Dear Sir | Yours very faithfully | Ch. Darwin

1
The date is established by the relationship between this letter, the letter to J. D. Hooker, [28 April 1866], and the letter to William Robinson, 5 May [1866]. In 1866, the intervening Sunday was 29 April.
2
CD was in London from 21 April to 1 May 1866 (Emma Darwin’s diary (DAR 242)). In the letter to J. D. Hooker, [28 April 1866], he wrote that he would return home on Monday 30 April, or Tuesday 1 May 1866.
3
No letter from William Robinson offering assistance has been found.
4
On CD’s interest in Euryale ferox, see the letter to J. D. Hooker, [28 April 1866] and n. 6.

Manuscript Alterations and Comments

2.2 (though … aid me)] parentheses over commas
2.3 one flower] ‘one’ interl
2.5 the seeds] ‘the’ interl
2.8 advanced] after del ‘been’
3.3 expanded] above del ‘open’

Please cite as “DCP-LETT-5072,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-5072