To George Bentham   18 December [1857]1

Down Bromley Kent

Dec. 18th

My dear Sir

I am very much obliged for answers which were just what I wanted & quite as explicit as I expected.—2 I have had already occasion to put in a salvo about doubtful identification of plants experimentised on.—3 Cucubalus viscosus & Italicus are extremely sterile together as might have been expected from what you say. All the other forms are extremely fertile, only one degree below normal fertility, & which one degree of lessened fertility may, I believe, be accounted for by the requisite manipulation &c.—

Anyhow Gærtner finds the same slight degree of lessened fertility (or rather a greater degree of infertility) between Cowslip & Primrose, & the Blue & Red common Anagallis—4

With very many thanks | Yours sincerely | C. Darwin

3
CD perhaps refers to his remarks concerning Karl Friedrich von Gärtner’s crosses of Datura stramonium and D. tatula that ‘it may be questioned … whether these forms should be considered as anything but varieties.’ (Natural selection, p. 404).
4
See Natural selection, p. 405.

Manuscript Alterations and Comments

2.1 (or … infertility) 2.2] parentheses over commas

Please cite as “DCP-LETT-2189,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-2189