From T. H. Farrer 5 May 1869
3 Gloucester Terrace | Regents Park
5 May /69
My dear Mr Darwin
You asked me last year what I meant by the “degraded” structure of Viola Odorata.—1 I think now, looking at the flowers again, the word was justified. In “Viola Tricolor” admirably described in Hildebrand, there is an apparatus for cross fertilization by insects almost as wonderful and complete as that of the Orchises.2 In Viola Cornuta, it is even still more elaborate.
In Viola Canina there is the same structure: but in almost every particular, less complete.— The flower less conspicuous: less open: the lower petal less coloured & less displayed: the anthers less syngenesious: good pollen less universal & smaller in quantity: and above all the style & stigma less adapted either in position or form to catch the pollen from the proboscis of the bee. Consequently Viola Canina does sets some seeds from open flowers—but not constantly or frequently as in Viola Tricolor.
In Viola Odorata the deficiencies of V. Can. are much increased. The nature & position of the footstalks: of the sepals: the colour & position & shape of the petals make the flower one of the most inconspicuous there is—and the way to the nectary is no “royal road”— The anthers seldom have good pollen. And the form &c of style & stigma though similar in generally to that of V. tricolor has lost the peculiarities & use which give it a meaning. Consequently it is very seldom that open flowers of Viola odorata set their seed.
Is there not here a gradation or degradation, shewing how an elaborate structure originally full of function & purpose becomes comparatively meaningless & useless.
Very truly yours | T H Farrer
CD annotations
Footnotes
Bibliography
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Summary
Justifies his use of term "degraded" by comparing contrivances for cross-fertilisation in different species of Viola.
Letter details
- Letter no.
- DCP-LETT-6727
- From
- Thomas Henry Farrer, 1st baronet and 1st Baron Farrer
- To
- Charles Robert Darwin
- Sent from
- London, Regents Park
- Source of text
- DAR 111: A79–80
- Physical description
- ALS 4pp †
Please cite as
Darwin Correspondence Project, “Letter no. 6727,” accessed on 23 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-6727.xml
Also published in The Correspondence of Charles Darwin, vol. 17