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Darwin Correspondence Project

To Asa Gray   25 June 1874

Down, | Beckenham, Kent.

June 25th 74

My dear Gray

I said in my last note that I was at work on Pinguicula.1 Well it proves an excellent digester of fibrin; albumin, meat, &c. It has also interested me to find that if a row of flies be placed near the margin, the edge of the leaf in the course of 2 or 3 hrs turns over, so as to bring the secreti〈ng〉 and absorbing glands into contact with the upper as well as the lower surface of the flies. But the point which has interested me most is that the leaves certainly absorb nutritious matter from little leaves & seeds which are blown onto them. Hence the plant is certainly not only insectivorous, but graminivorous & granivorous! I have had a lot of leaves sent me from N. Wales;2 & it is extremely rare to find a single leaf without more than one captured insect. Each had also more than one leaf, on an average of some other plant adhering to them; and two seed-capsules   But it is rather too early in the year I suppose for seeds. Now does Pinguicula grow anywhere near you? & if so would you look to a certain number of leaves, & tell me whether you find any seeds (& kinds) or leaves of other plants adhering to them. This would be valuable aid. It will amuse me much to make a good case about the omnivorous habits of this plant3

Yours very sincerely | Ch. Darwin


See letter to Asa Gray, 3 June [1874]; CD’s most recent letter to Gray, of 5 June [1874], does not mention Pinguicula (butterwort). CD’s notes on his observations and experiments on digestion in Pinguicula in June 1874 are in DAR 59.1: 35–63.
The specimens were sent by Amy Ruck; see letter to W. T. Thiselton-Dyer, 23 June 1874 and n. 3. The records of CD’s experiments on those specimens, carried out between 23 and 27 June 1874, are in DAR 59.1: 57–63.
CD published his observations and experiments on digestion in Pinguicula in Insectivorous plants, pp. 368–95, concluding that it was adapted to digest soluble nitrogenous matter and was ‘partly a vegetable as well as an animal feeder’ (ibid., p. 390).


Insectivorous plants. By Charles Darwin. London: John Murray. 1875.


Remarks on his work on Pinguicula. Notes its digestive power; it absorbs nutritious matter from leaves and seeds as well as insects.

Letter details

Letter no.
Charles Robert Darwin
Asa Gray
Sent from
Source of text
Archives of the Gray Herbarium, Harvard University (108)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9511,” accessed on 17 April 2021,

Also published in The Correspondence of Charles Darwin, vol. 22