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Letter 7150

Müller, J. F. T. to Darwin, C. R.

29 Mar 1870

Summary

His observations on mimicry in butterflies

and self-sterility in plants.

Transcription

Itajahay, Sa Catharina, Brazil

March 29. 1870.

My dear Sir

I have been detained from answering sooner your letter ofDecbr. 1st, by an excursion into our primeval forests and afterwardsby a severe illness of one of my daughters.f1 And now, I must firstexpress my cordial thanks for a copy of No 1 of “the Academy”and for the German translation of Wallace’s exceedingly interestingwork on the Malay Archipelago.f2 One of the points, which haveinterested me most in this work, is the dimorphism and mimicry ofseveral butterflies.f3 My attention having thus been calledto our endemic butterflies, I have met also with several cases ofclose ressemblance of species belonging to distinct genera, which mustprobably be attributed to mimicry. There is, for instance a verycommon Pieris (1), and three or four other rather rare species,when seen from above, are more or less closely imitating the coloursof this Pieris.—

I am much obliged for your account on Eschscholtzia;f4 the influenceof external conditions on the self-fertility of this ⟨foot of page,probably containing diagram, excised⟩ species is verycurious; it is shown in a striking manner by a plant, which I hadraised 1868 from your seeds and which only flowered 1869.—f5 Theother plants from the same seeds, which flowered the first year (1868)had retained self-fertility in a small degree; but this plant, whichflowered only the second year, and had thus been exposed for a farlonger time to our climate, proved perfectly self-sterile; it has beenleft uncovered, but growing at some distance from the other plants,which flowered at the same time, it produced by itself only a fewvery poor pods containing not even a single seed. Two flowersfertilised by pollen of a distinct plant yielded large pods, oneof which contained 115 seeds.—

I have been much pleased by hearing from Alex. Agassiz, thathe is now inclining to your views.f6 I think very high of him as oneof the most skilful and conscientious observers. His “Embryologyof the Starfish” is a master-piece.—f7

I gave you, in my last letter, some cases of plants, the firstflowers of which had a larger number of petals or stamens than thelater ones.f8 I have since found, in a tree of C⟨assia⟩ multijuja, that thefirst flowers of ⟨foot of page excised

DAR 76: B36

true

Footnotes

f1
Müller refers to the letter to Fritz Müller, 1 December [1869](Correspondence vol. 17). Müller had six surviving daughters (seeWest 2003).
f2
The first issue of the Academy, dated 9 October 1869, contained areview of the English translation of Müller’s Für Darwin (Dallastrans. 1869; Academy 1 (1869–70): 14–15). Müller also refers to Wallace 1869c (see Correspondencevol. 17, letter to Fritz Müller, 1 December [1869]).
f3
See Wallace 1869a, 1: 199–207.
f4
See Correspondence vol. 17, second enclosure to letter to FritzMüller, 1 December [1869].
f5
See Correspondence vol. 16, letters from Fritz Müller, 22 April1868, 9 September 1868, and 31 October 1868, and Correspondence vol. 17,letters from Fritz Müller, 12 January 1869 and 18 October 1869.
f6
Müller refers to Alexander Agassiz (see also Correspondencevol. 17, letter to Fritz Müller, 1 December [1869]).
f7
A. Agassiz 1864.
f8
See Correspondence vol. 17, letter from Fritz Müller, 18 December 1869.
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