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Darwin Correspondence Project

From W. E. Darwin   1 August 1862

Southampton & Hampshire Bank, Southampton

Aug 1 1862

My Dear Father,

I have got your Lythrum letter, and will send you the 3 kinds tonight. it certainly will be most awfully complicated work with 18 possible crosses.1 there is as much Lythrum as you like to be got here. when I first found a bed, or rather beds along a stream, I gathered haphazards parts of 27 different plants, and examined them when I got home.2 it is very odd the symmetry the the division had

out of the 27 plants

11 of them were long pistilled = Lp

9 — short — = Sp

7 — middle — = Mp.

You see the short are exactly a 13   the Lp—2 above the 13, the Mp—2 below the 13.

If you liked I could gather 90 or 120 or 150 or 300 plants and class them. there is one odd thing if true, that would I should make it less complicated; all the Lp that I have looked at yet are less ripe or advanced than the Sp or the Mp.

This was plain in the 27 plants, (unless of course I have made some hideous mistake)

when the pollen is ripe and the anthers are opening, the filament is crimson and the pollen green— in these 27 plants the filaments were crimson and the pollen green in all the long stamens (only of course of the quite open flowers) both of the Sp and of the Mp.— while in all the 11 heads of the Lp there was not a single red filament or green pollen to be seen—and I looked tolerably carefully through them all.

I have looked at the two pollen of the Lp, and drawn and measured them by Camera Lucida and there is a decided difference.3

there is also difference I think between the pollens of the different kinds, but you will see all that.

I had gathered a lot more yesterday to have another look, but with the family luck my mare tumbled crossing her legs and cut her knee very badly, and in the scrummage all the plants tumbled out of my case

CD annotations

1.1 I have … home. 1.5] crossed pencil
2.2 ‘/27added under column of numbers, pencil
3.1 If you … my case 8.3] crossed pencil


CD’s letter has not been found; however, in the letter to Daniel Oliver, 29 [July 1862], CD described the crosses he planned to make with the three forms of Lythrum salicaria. See also letter to W. E. Darwin, 9 July [1862].
William’s observations on the twenty-seven Lythrum plants, dated 26 July 1862, are detailed in his botanical notebook (DAR 117: 36–7). See also William’s earlier observations on Lythrum, dated 13 July and 20 July, in DAR 117: 1, 12–13.
In the letter from W. E. Darwin, 5 August 1862, William enclosed camera lucida drawings, dated 1 August 1862, of the two sets of pollen grains from the long and short stamens of the long-styled form of Lythrum salicaria.


WED has been collecting Lythrum plants. Numerical proportions of the three forms.

Letter details

Letter no.
William Erasmus Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 162: 90
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3675,” accessed on 1 December 2022,

Also published in The Correspondence of Charles Darwin, vol. 10