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Darwin Correspondence Project

From W. E. Darwin   8 May [1863]1


May 8.

My Dear Father,

I sent off this morning a box containing two heads of Anchusa.2 The pollen of short pistilled is decidedly the largest and there is most of it. I have entirely forgotten to look whether both bear seeds; but I will.3 I am going to the isle of Wight on Sunday when I will mark some plants.4

I know whether you have examined Corydalis carefully; it seems almost as nicely arranged as Orchis.5

The two side petals form a hood over stigma enclosing it entirely, as soon as the pollen is mature it all falls into the cuplike-stigma   when enclosed by the hood, then the back petal that is the one facing the nectary petal falls back and leaves the pistil just on the balance within the hood. This back petal prevents the hood coming off the stigma and it never seems to fall back till the stigma cup is full of pollen.

As soon as the back petal falls back, the least touch sends out the pistil with a bound. Carrying the pollen with it the stigma and style on bounding out fit exactly into the groove leading down to the nectary. But instead of the stigma going straight into the groove from a natural twist in the style it goes in side ways, so that as it buries itself at base of groove nearly all the pollen is pulled out by the friction and is left against side of groove in position for bees to take it, at the same time leaving stigma almost bare to receive other pollen.

So as to prevent the proboscis penetrating except at proper side (or at base?) of groove there is curve in side of groove which makes a sort of overhanging ledge.

Is this the same in fumitories?6 As it is a beautiful arrangement making the pistil carrying the pollen in position for another flower.

I am glad to find you have managed to get to Leith hill.7

Your affect son | W. E Darwin

Tell me whether I am right about Corydalis

CD annotations

1.1 I sent … plants. 1.4] crossed ink
End of letter: ‘(Wild white Corydalis near Southampton.)’ pencil, square brackets in MS


The year is established by the relationship between this letter and the letter from W. E. Darwin, 4 May [1863].
The plant was subsequently identified as Pulmonaria angustifolia (see letter from W. E. Darwin, 4 May [1863], n. 1).
CD had asked William to make these observations on Anchusa (Pulmonaria angustifolia) to clarify the form of dimorphism exhibited by the flowers of this species (see letter to W. E. Darwin, [5 May 1863]).
William’s observations on the sizes of pollen-grains in the different forms of flower in Pulmonaria angustifolia are discussed in Forms of flowers, p. 106; his original notes have not been found. According to his botanical notebook (DAR 117: 67), William visited the Isle of Wight to mark plants on 10 May 1863, but returned too late in the season to collect seed and had to repeat the work in 1864. CD’s brief pencil notes on the information on this species sent by William in 1863 are in DAR 110: 41–2.
William’s observational notes and sketches relating to Corydalis claviculata and C. lutea are in his botanical notebook (DAR 117: 61–2) and his botanical sketchbook (DAR 186: 43, pp. 48–9). See also letter to W. E. Darwin, [10 May 1863] and n. 4.
See letter to W. E. Darwin, [10 May 1863], n. 5. William’s comparative observations on ‘Fumitory’ (Fumaria) are preserved in DAR 117: 63. Like Corydalis, Fumaria is a genus of the family Fumariaceae (J. C. Willis 1973).
Leith Hill Place, near Dorking, Surrey, was the home of Josiah Wedgwood III. According to Emma Darwin’s diary (DAR 242), the Darwins stayed at Leith Hill Place from 6 to 13 May 1863.


Describes the structure of Corydalis and its arrangement for making pollen accessible to bees.

Letter details

Letter no.
William Erasmus Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 76: B188–90
Physical description
5pp †

Please cite as

Darwin Correspondence Project, “Letter no. 4147,” accessed on 25 March 2019,

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