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Darwin Correspondence Project

To Maxwell Tylden Masters   6 April [1863]1

Down. | Bromley. | Kent. S.E.

April 6th

My dear Sir

I have been very glad to read your Paper on Peloria.2 For mere chance of following case being new, I send it. A plant, which I purchased as Corydalis tuberosa has, as you know, one nectary short, white & without nectar; the pistil is bowed towards the true nectary; & the hood formed by the inner petals slips off towards opposite side (all adaptations to insect agency like many other pretty ones in this Family). Now on my plants there are several flowers (the fertility of which I will observe) with both nectaries equal & purple & secreting nectar; the pistil is straight & the hood slips off either way. In short these flowers have exact structure of Dielytra, & Adlumia. Seeing this I must look at this case as one of Reversion;3 though it is one of the spreading of irregularity to two sides.

As Columbine has all petals &c. irregular & as Monk’s hood has two petals irregular, may not the case given by Serringe & referred to you by you be looked at as Reversion to the Columbine State.?4 would it be too bold to suppose that some ancient Linaria or allied form, & some ancient Viola had all petals spur-shaped, & that all cases of “irregular peloria” in these genera are Reversions to such imaginary ancient form?—5

It seems to me, in my ignorance, that it would be advantageous to consider the two forms of Peloria, when occurring in the very same species, as probably due to same general law viz one as reversion to very early state, & the other as reversion to a later state when all the petals were irregularly formed. This seems at least to me a priori a more probable view; than to look at one form of Peloria as due to Reversion & the other as something distinct.6

What do you think of this notion?—

My dear Sir | Yours sincerely | Ch Darwin.


The year is established by the relationship between this letter and the letter to M. T. Masters, [8–13 April 1863].
Masters 1863.
CD discussed Corydalis in the chapter of Variation that concerned reversion (Variation 2: 28–61); he had just completed a draft of this chapter, together with two others on inheritance (Variation 2: 1–84), on 1 April 1863 (see ‘Journal’ (Correspondence vol. 11, Appendix II)). Corydalis tuberosa and Masters 1863 are discussed in Variation 2: 58–9. CD argued that the ‘coadapted modifications’ of two full nectaries functioning for ‘insect agency’ could not be attributed to chance, or to correlated variability; he suggested that such modifications should be attributed to ‘reversion to a primordial condition of the species’ (Variation 2: 59). See also n. 5, below. There are two notes in DAR 51 recording CD’s observations on C. tuberosa, the first of which is dated 3 April 1863 (DAR 51: B16–17). Dielytra and Adlumia, like Corydalis, are genera in the family Fumariaceae.
In his paper on peloric flowers (Masters 1863), Masters noted that in some garden varieties of columbine (Aquilegia), the irregularity disappeared almost entirely. He cited Nicolas Charles Seringe’s description of a peloric flower in Aconitum (monks-hood) (Seringe 1823, 1: 132): ‘all the sepals were helmet-shaped and all the petals presented that peculiar form, which, under ordinary circumstances, is assumed by two only, the other three being reduced to the condition of mere scales’ (Masters 1863, p. 260). Aquilegia and Aconitum are genera in the family Ranunculaceae.
CD was exploring the possibility of reversion in a species with several irregular parts of the flower to a form in which all parts were irregular (as in irregular peloria). In Masters 1863, Masters proposed the division of peloria, or regularity in normally irregular flowers (what the author called exceptions to the ‘ordinary rule of floral structure’, p. 258), into two categories. He suggested the term ‘regular or congenital peloria’ for cases where flowers ‘contrary to their usual habit, retain throughout the whole of their growth their primordial regularity of form and equality of proportion’. The term ‘irregular or acquired peloria’ would designate flowers in which the ‘irregularity of growth that ordinarily characterizes some portions of the corolla is manifested in all of them’, resulting in a regular flower (ibid., p. 260). See also Variation 2: 58–60.
See Variation 2: 58–60.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Seringe, Nicolas Charles. 1823. Musée Helvétique d’Histoire Naturelle. (Partie botanique.) Ou collection de mémoires, monographies, notices botaniques … par N. C. Seringe. Berne, Switzerland: J. J. Burgdorfer.

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


Comments on MTM’s article ["On the existence of two forms of peloria", Nat. Hist. Rev. n.s. 3 (1863): 258–62]. Cites interesting case of peloric flower.

Letter details

Letter no.
Charles Robert Darwin
Maxwell Tylden Masters
Sent from
Source of text
Catherine Barnes (dealer) (January 2002)
Physical description
4pp & C 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 4076,” accessed on 5 May 2021,

Also published in The Correspondence of Charles Darwin, vol. 11