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Letter 7184

Darwin, C. R. to Müller, J. F. T.

12 May 1870


Crossing experiments and self-sterility [in Eschscholzia].


Hermann Müller on insect adaptations for fertilisation of flowers.

CD working on book on man and sexual selection.


Down Beckenham | Kent

May 12. 1870

My dear Sir

I thank you for your two letters of Dec 15 & Mar 29, bothabounding with curious facts.f1 I have been particularly glad to hearin yr last about the Escholtzia; for I am now rearing crossed &self-fertilized plants, in antagonism to each other, from yoursemi-sterile plants, so that I may compare their comparative growthwith that of the offspring of English fertile plants.f2 I have forwardedyour post script about Passiflora with the seeds, to Mr Farrer,who I am sure will be greatly obliged to you; the turning up of thependant flower plainly indicates some adaptation.f3 When I next go toLondon I will take up the specimens of butterflies & shew them toMr Butler of the British Museum, who is a learned lepidopterist& interested on the subject.f4 This reminds me to ask you whether youreceived my letter about the ticking butterfly described at p. 33of my Journal of researches; viz whether the sound is in any waysexual? Perhaps the species does not inhabit yr island.f5

The case described in yr last letter of the trimorphic monocot.Pontederia is grand. I wonder whether I shall ever have time torecur to this subject; I hope I may, for I have a good deal ofunpublished material.f6

I thank you for telling me about the first-formed flowers havingadditional petal, stamens, carpels &c; for it is a possible meansof transition of form: it seems also connected with the fact onwhich I have insisted of peloric flowers being so often terminal.f7As pelorism is strongly inherited (I have just got a curious caseof this in a legum. plant from India); would it not be worth whileto fertilise some of your early flowers having additional organswith pollen from a similar flower, & see whether you cd not makea race thus characterised? Some of yr abutilons have germinated,but I have been very unfortunate with most of your seed.f8 You willremember having given me in a former letter an account of a verycurious popular belief in regard to the subsequent progeny of asses,which have borne mules; & now I have another case almost exactly likethat of Lord Morton’s mare, in which it is said the shape of the hoofsin the subsequent progeny are affected.f9

(Pangenesis will turn out true some day!)f10

A few months ago I recd an interesting letter & paper from yrbrother, who has taken up a new & good line of investigation, vizthe adaptation in insects for the fertilisation of flowers.f11

The only scientific man I have seen for several months is Köllikerwho came here with Günther & whom I liked extremely.f12

I am working away very hard at my book on man & on sexualselection, but I do not suppose I shall go to press till latein the autumnf13

Believe me my dear Sir | with many thanks for all yr kindness | yours sincerely | Ch. Darwin

British Library Board (Loan 10:32)



See letters from Fritz Müller, 18 December 1869 (Correspondencevol. 17) and 29 March 1870. CD evidently wrote ‘15’ in error.
In his letter of 29 March 1870, Müller had reported his mostrecent results with plants of Eschscholzia californica raised fromseeds sent by CD. CD reported the results of his experiments in Crossand self fertilisation, pp. 109–17; 262–3.
For the postscript referred to, see the letter from Fritz Müller, 16 February 1870. Müller had enclosed seeds of Passiflora. ThomasHenry Farrer had been studying the fertilisation mechanisms ofPassiflora (see Correspondence vol. 17).
No letter from Müller mentioning specimens of butterflies hasbeen found. CD refers to Arthur Gardiner Butler.
See Correspondence vol. 17, letter to Fritz Müller, 8 September[1869] and n. 2. The ticking butterfly was Papilio feronia (nowHamadryas feronia, the blue cracker), which is found where Müllerlived in Santa Catarina province (now state), Brazil. See Journal ofresearches 2d ed., p. 33. Müller moved to the mainland in1867, but had previously lived at Destêrro (now Florianópolis) onSanta Catarina Island.
See Correspondence vol. 17, letter from Fritz Müller, 18 December 1869 and n. 3. Müller published on the three forms ofPontederia (now Eichhornia, the water hyacinth) in F. Müller 1871. CD discussed it in Forms of flowers, pp. 183–7.
In his letter of 18 December 1869 (Correspondence vol. 17),Müller had described peloric flowers of Agapanthus and Jussiaea,a synonym of Ludwigia. In Variation 2: 345–7, CD discussed thetendency of terminal or central flowers to be peloric.
Müller had sent seeds of Abutilon with his letter of 18 October1869 (Correspondence vol. 17; see ibid., letter to Fritz Müller,1 December [1869]).
The letter in which Müller discussed the offspring of asses hasnot been found, but see the letter to J. J. Weir, 17 March [1870], inwhich CD quoted a passage from Müller on the topic. See also the letterfrom J. J. Weir, 17 March 1870 and n. 1 for more on the mare of LordMorton (George Sholto Douglas).
CD refers to his hypothesis of pangenesis, a theory of hereditydescribed in Variation 2: 357–404.
See letter from Hermann Müller, 8 March 1870 and n. 2.
Rudolf Albert von Kölliker and Albert Günther visited Down on15 April 1870 (see letter from Albert Günther, 12 April 1870).
CD refers to Descent, which went to press on 30 August 1870 (seeCD’s ‘Journal’ (Appendix II)).
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