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Darwin Correspondence Project

To J. D. Hooker   28 November [1871]1

Down, | Beckenham, Kent.

Nov. 28th

My dear Hooker

If you had come here on Sunday, I shd. have asked you whether you could give me seed or seedlings of any Melastomatid which would flower soon to experiment on!! I wrote also to J. Scott to ask if he could give me seed.2 Several years ago I raised a lot of seedlings of a Melastomatous, Greenhouse bush (Monchætus or some such name) from stigmas fertilised separately by the two kinds of pollen, & the seedlings differed remarkably in size & whilst young in appearance; & I never knew what to think of the case (so you must not use it) & have always wished to try again; but they are troublesome beasts to fertilise.3 On other hand I could detect no difference in the product from the 2-coloured anthers of Clarkia.—4 If you want to know further particulars of my experiments on Monochaetus (?) & Clarkia, I will hunt for my notes.— You ask about difference in pollen in the same species.5 All dimorphic & trimorphic plants present such difference in function & in size. Lythrum & (the trimorphic) Oxalis are the most wonderful cases.6 The pollen of the closed imperfect cleistogenic flowers differs in the transparency of the integument, & I think in size. The latter point I cd ascertain from my notes.—7 The pollen or female organs must differ in almost every individual in some manner; otherwise the pollen of vars. & even distinct individuals of same vars would not be so preptent over the individual plants own pollen. Here follows a case of individual difference in function of pollen or ovules or both. Some few individuals of Reseda odorata & of R. lutea, cannot be fertilised, or only very rarely, by pollen of same plant, but can by pollen of any other individual. I chanced to have 2 plants of R. odorata in this state; so I crossed them, & raised 5 seedlings, all of which were self-sterile & all perfectly fertile with pollen of any other individual mignonette.8 So I made a self-sterile race! I do not know whether these are the kinds of facts which you require. Think whether you can help me to seed or better seedlings (not cuttings) of any Melastoma.—

We were all very very sorry that you did not appear on Sunday, & shall be very glad to see with Mr Palgrave (if he is inclined to come) you any day.9 But Next Sunday our house will be full.10 We go to London on Decr. 14th.—for a week. to Erasmus.11 6. Queen Anne St. Thank you much for telling me about the Ayrton affair—12 I am timorous, for I believe politicians are such cowards & so false, & care so little about scientific men, that they will throw any one over board even for such a scamp as Ayrton.

Yours affectionately | C. Darwin

Footnotes

The year is established by the relationship between this letter and the letter to John Scott, 1 November 1871.
CD had requested seed from plants in the family Melastomaceae (now Melastomataceae) in the letter to John Scott, 1 November 1871.
CD experimented with Monochaetum ensiferum, which has two sets of stamens carrying differently coloured pollen (red and pale yellow). CD’s diagrams and notes on the species are dated between January 1862 and May 1863 (DAR 205.8: 22–41); he did further experiments in 1875 and 1881 (DAR 205.8: 42–3, 58–9).
CD’s notes on Clarkia elegans, dated between October 1862 and June 1863, are in DAR 205.8: 6–7, 51–3.
Hooker’s letter has not been found.
CD experimented extensively with species of Lythrum and Oxalis in 1863 and 1864 (see Correspondence vols. 11 and 12, ‘Three forms of Lythrum salicaria’, and Forms of flowers, pp. 137–83). For a discussion of the relative size of pollen-grains in dimorphic and trimorphic plants, see Forms of flowers, pp. 248–52.
The pollen-grains of cleistogamic flowers have especially thin, transparent coats (see Forms of flowers, p. 310). CD measured the size of pollen-grains in cleistogamic flowers of Viola canina and Leersia oryzoides (see ibid., pp. 315 and 334). His notes on Leersia, dated May and June 1863, are in DAR 111: A6, A8; his notes on Viola, dated June 1866, are in DAR 111: A38.
CD describes this experiment with Reseda odorata (mignonette) in Cross and self fertilisation, p. 339.
CD probably refers to Hooker’s cousin, William Gifford Palgrave.
Emma Darwin’s diary (DAR 242) records that ‘Ellen T.’ and ‘Swettenham’ visited on 2 December 1871. This was probably Ellen Harriet Tollett and Richard Paul Agar Swettenham.
According to CD’s ‘Journal’ (Appendix II), CD stayed in London with his brother Erasmus Alvey Darwin from 14 to 22 December 1871.
On Hooker’s dispute with Acton Smee Ayrton, see the letter from J. D. Hooker, 2 November 1871 and nn. 1 and 2.

Summary

CD is considering repeating experiments on melastomads in which different pollen sizes produced differing seedling sizes.

Responds to JDH’s query on differences in pollen within the same species.

Letter details

Letter no.
DCP-LETT-8087
From
Charles Robert Darwin
To
Joseph Dalton Hooker
Sent from
Down
Source of text
DAR 95: 445–8
Physical description
7pp

Please cite as

Darwin Correspondence Project, “Letter no. 8087,” accessed on 25 June 2019, http://www.darwinproject.ac.uk/DCP-LETT-8087

Also published in The Correspondence of Charles Darwin, vol. 19

letter