Ɛpsilon

To T. H. Farrer   4 July [1874]1

Down, | Beckenham, Kent.

July 4th

My dear Farrer

I have read with much interest your article.2 It certainly is a very curious case. The older I grow the more I become impressed with the endless & unfathomable fluctuations of structure.— I do not much like C. Emerus; if I understand rightly the bowing of the claw of the vexillum becomes the sole adaptation for getting honey on the outside of the flower.3 I wonder whether other Pap. flowers have an elongated claw. Hooker will be here next Saturday & I will ask him.4

The only case, at all analogous to yours, of which I can think is Marcgravia of S. America, which has its sepals or bracts (I forget which) modified into nectariferous tubes, so placed that the visitors brush against the stamens & stigmas.5 As I have often said, you were a born naturalist.—

Yours most sincerely | Ch. Darwin

1
The year is established by the reference to Farrer’s article (see n. 2, below).
2
Farrer’s article, ‘Fertilisation of papilionaceous flowers—Coronilla’ (Farrer 1874), appeared in Nature, 2 July 1874.
3
In Farrer 1874, p. 169, Farrer had described and illustrated how the claw or base of the vexillum (the large central petal of a papilionaceous flower) in Coronilla emerus (now Hippocrepis emerus, scorpion senna) was elongated and straight with the upper part of the petal curved inward towards the base.
4
Joseph Dalton Hooker visited CD on Saturday 11 July 1874 (Emma Darwin’s diary (DAR 242)).
5
Flowers in many species of the tropical genus Marcgravia have modified bracteoles that act like nectaries.

Manuscript Alterations and Comments

1.4 getting] after del ‘rea’
1.6 claw.] point over comma
1.6 here] interl

Please cite as “DCP-LETT-9531,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9531