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Darwin Correspondence Project

From W. E. Darwin   12 May [1864]


May 12.

My Dear Father,

At last I have finished the Pulmonaria.1 I went over the day before yesterday, & collected a good number,2 I am going to tell all that I looked to though it probably will not be much use.

I gathered 150 stems from different plants and separated them into bundles of Long & short to judge of sizes, I found 95 were long, 45 short. When I compared the bundles, I had very little doubt that the long styled were the largest on the whole, both varied a good deal in size, but among the long styled there were none so small as among the shortstyled. And also there were none so large among the short styled as there were among the long. And I think the average or medium size of the long was greater than that of the short.3

(On looking at the bundles I thought the short styled seemed more withered or passed, so I gathered 29 fresh flowers of which 22 were short s & only 7 long; I found 7 of the short had 66 flowers & buds & 86 with corollas gone. The 7 long styled had 51 flowers & buds, 64 with corollas gone, but when I took the average for 7 flowers from the whole 21 of the short styled I found 64 flowers & buds, 65 flowers gone)

I have bracketed this as not worth reading so that on the whole it does not shew anything but I think the short styled bear more flowers than the long.

for 7 Short styled stems had 152 flowers in all

7 Long styled "  —115 Do—

and the average for 7 shortstyled calculated from the 21 was 129 flowers in all.

This morning I took 10 stems of each kind

the 10 shortstyled had 190 flowers in all

10 Longstyled — 169 —Do

I think this looks as if the short styled bore the most flowers,4 & make it more certain that the long styled are the largest.

I have drawn anthers as you see of 6 of each kind   I have made duplicate drawings of some, as I was not quite sure of my drawing,5 the Long styled seem to have the longest anthers, as if you take BV the smallest longstyled anther, it is larger than 2 or 3 of the shortstyled.6

It was only an accident about the pin headed pistil, I have looked at a great many plants and they are all more or less bilobed.7 I could not make up my mind which kind had most pollen.8

I keep my flowers in water in case you want anything else.

Your affect son | W. E D



CD annotations

7.3 to have … shortstyled. 7.4] double scored, pencil

8.1 It was … bilobed 8.2] scored pencil Bottom of first page:

‘ 95 ’ 55 pencil — 150

Cover, recto: ‘May 13th 1864’ pencil; ‘4’ red crayon, circled red crayon 10 Cover, verso: ‘May 13 1864 | Pulmonaria | (number of Plants of both forms) | Short-styled more flowers | see Hildebrand11 | Length of anthers’ pencil Top of enclosure: ‘May 12thpencil Enclosure, verso: ‘Shape & size of Anthers’ pencil


William refers to his observations, measurements, and collections of Pulmonaria angustifolia, and to his drawings of anthers (see n. 2 below, and enclosure). William had been assisting CD’s work on P. angustifolia since May 1863; CD was keen to investigate dimorphism in Pulmonaria, and to detect variable flower structures associated with heterostyly (see letter to W. E. Darwin, 3 May [1864] and nn. 1 and 2; see also Forms of flowers, pp. 3–9).
William collected Pulmonaria angustifolia on the Isle of Wight in 1863 and 1864 (see letter from W. E. Darwin, 18 April 1864 and nn. 2 and 3).
CD recorded William’s observations of relative corolla sizes on long-styled and short-styled forms of Pulmonaria angustifolia in Forms of flowers, p. 105. See CD’s notes on P. angustifolia’s corolla size in DAR 109: A50, A56, A57b, and DAR 110: A43 v., A51, A53. For CD’s general comments on corolla size in heterostyled plants, see Forms of flowers, pp. 246–7.
CD published William’s counts of flowers per ten stems of each form of Pulmonaria angustifolia in Forms of flowers, p. 107, noting that Friedrich Hildebrand found an even greater difference for P. officinalis (see DAR 110: A53, and n. 11, below).
See enclosure, and William’s comment at the bottom right of the drawing. William also included drawings of an anther from each form in his memorandum of 6 May 1864.
The long-styled anther that William labelled BV was larger than the short-styled anthers labelled A II, A IV, and A VI. For CD’s interest in anther size, see the letter to W. E. Darwin, 3 May [1864] and n. 2.
See letter to W. E. Darwin, [after 14 April – 5 May 1864] and nn. 3 and 4. William included sketches of Pulmonaria angustifolia stigmas with his memorandum of 6 May 1864.
The diagram is reproduced at 45 per cent of its original size.
The ‘4’ in red crayon corresponds to CD’s numbered abstracts of William’s letters on Pulmonaria angustifolia in DAR 110: A53 (see letter from W. E. Darwin, 14 April [1864] and n. 10).
CD may have added this annotation after receiving the letter from Friedrich Hildebrand of 21 June 1864, in which Hildebrand mentioned his experiments on dimorphism in Pulmonaria officinalis. Hildebrand published his results in Hildebrand 1865; CD referred to his observation of the greater number of flowers produced by the short-styled plants of P. angustifolia in Forms of flowers, p. 107.


Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.


Observations on style length of 150 flowers of Pulmonaria [angustifolia]. [See Forms of flowers, p. 105.]

Letter details

Letter no.
William Erasmus Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 110: A66–7
Physical description
ALS 4pp †, diags 2pp †

Please cite as

Darwin Correspondence Project, “Letter no. 4492,” accessed on 20 May 2024,

Also published in The Correspondence of Charles Darwin, vol. 12