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Darwin Correspondence Project

To Grant Allen   2 January 1882

Down, | Beckenham, Kent. | (Railway Station | Orpington. S.E.R.)

Jan 2d. 1882

My dear Sir

I thank you for sending me the Cornhill, as your article has interested me much.—1 Many years ago I thought it highly probable that petals were in all cases transformed stamens. I forget (excepting the water-lily) what made me think so; but I am sure that your evolutionary argument never occurred to me, as it is too striking & apparently valid ever to be forgotten.—2

I cannot help doubting about petals being naturally yellow: I speak only from vague memory, but I think that the filaments are generally white or almost white, & surely it is the filament which is developed into the petal.3 I remember some fine purple & bright yellow filaments, but these seemed to me to serve by adding colour to the whole flower. Is it not the pollen alone which renders most stamens yellow at a cursory glance? You may possibly like to hear that I have described cases (& others have been described) when an excessively poor soil has rendered a flower double. I can hardly doubt that any great change of conditions (which has so strong a tendency to cause sterility) tends to render a flower double.—4 Close interbreeding has a slight tendency in this direction, as has according Gärtner, a hybrid origin.—5

With many thanks for the pleasure which your article has given me, I remain | Yours sincerely | Ch. Darwin

I suppose that you know H. Müllers Alpen-Blumen, as it contains much about colour of flowers & orders of visting insects.6 I much doubt Wallace’s generalisation about much modified parts being splendidly coloured, except in so far that both have been acted on by the same cause, viz sexual selection.—7

That is an excellent case in the Voyage of the Vega, which I am reading, but have not yet got so far.8 In former times it wd. have been worth its weight in gold to me.—


The letter from Allen has not been found. He sent his article ‘The daisy’s pedigree’, which appeared in the August 1881 issue of Cornhill Magazine (Allen 1881).
Allen wrote: ‘petals … are merely specialised stamens, which have given up their original function of forming pollen, in order to adopt the function of attracting insects’ (Allen 1881, p. 175).
Allen claimed that the inner florets of the daisy evolved through a flattening and lengthening of the yellow corolla, and that the first rays or petals would also have been yellow (see Allen 1881, p. 180). CD briefly discussed petaloid stamens (or filaments) in Orchids, pp. 294 and 303, noting that in the Marantaceae, even fertile stamens are sometimes petaloid. See also Correspondence vol. 9, letter to J. D. Hooker, 10 November [1861].
In a letter to Gardeners’ Chronicle, [late August 1843] (Correspondence vol. 2; Shorter publications, pp. 165–6), CD had discussed cases of double flowers appearing in the poorest soil, noting that the origin of double flowers had often been attributed to excess food: ‘Is it, then, too bold a theory to suppose that all double flowers are first rendered by some change in their natural condition, to a certain degree, sterile; and that their vessels being charged with organizable matter in excess, (which would be greatly formed by high cultivation,) it is converted into petals …?’ For more on double flowers, see Variation 2: 167–8, 171–2, 200.
Karl Friedrich von Gärtner; CD annotated the discussion of double flowers in his copy of Gärtner 1849, pp. 567–9 (see Marginalia 1: 289). By ‘close interbreeding’, CD meant plants fertilised with their own pollen (see Variation 2: 127).
Hermann Müller gave many examples of insects attracted to flowers of different colours in Alpenblumen, ihre Befruchtung durch Insekten: und ihre Anpassungen an dieselben (Alpine flowers, their fertilisation through insect agency and adaptations for this; H. Müller 1881, pp. 479–533).
Alfred Russel Wallace had been critical of CD’s theory of sexual selection and had presented various alternatives, such as protective mimicry and concealment; in males, he argued, bright colours were a sign of vitality, whereas females were often less conspicuous for the sake of protection (see A. R. Wallace 1878, pp. 217–18, Correspondence vol. 15, letter from A. R. Wallace, 26 April [1867], Correspondence vol. 25, letter from A. R. Wallace, 23 July 1877).
The voyage of the Vega round Asia and Europe (Nordenskiöld 1881, 2: 97). On the case of sexual selection, see the letter to G. J. Romanes, 1 January [1882] and n. 9.


Allen, Grant 1881b. The daisy’s pedigree. Cornhill Magazine 44: 168–81.

Gärtner, Karl Friedrich von. 1849. Versuche und Beobachtungen über die Bastarderzeugung im Pflanzenreich. Mit Hinweisung auf die ähnlichen Erscheinungen im Thierreiche, ganz umgearbeitete und sehr vermehrte Ausgabe der von der Königlich holländischen Akademie der Wissenschaften. Stuttgart: E. Schweizerbart.

Marginalia: Charles Darwin’s marginalia. Edited by Mario A. Di Gregorio with the assistance of Nicholas W. Gill. Vol. 1. New York and London: Garland Publishing. 1990.

Müller, Hermann. 1881a. Alpenblumen, ihre Befruchtung durch Insekten: und ihre Anpassungen an dieselben. Leipzig: W. Engelmann.

Nordenskiöld, Adolf Erik. 1881. The voyage of the Vega round Asia and Europe. Translated by Alexander Leslie. 2 vols. London: Macmillan and Co.

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.

Shorter publications: Charles Darwin’s shorter publications, 1829–1883. Edited by John van Wyhe. Cambridge: Cambridge University Press. 2009.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.

Wallace, Alfred Russel. 1878a. Tropical nature, and other essays. London: Macmillan and Co.


Thanks GA for his article ["The daisy’s pedigree", Cornhill Mag. 44 (1881): 168–81].

The evolutionary argument that petals are transformed stamens is "striking and apparently valid". Doubts petals are naturally yellow.

Wallace’s "generalization about much modified parts being splendidly coloured" is also dubious except as both are caused by sexual selection.

Letter details

Letter no.
Charles Robert Darwin
Charles Grant Blairfindie (Grant) Allen
Sent from
Source of text
Cleveland Health Sciences Library (Robert M. Stecher collection)
Physical description
ALS 5pp

Please cite as

Darwin Correspondence Project, “Letter no. 13594,” accessed on 15 July 2024,