From Fritz Müller 29 March 1870
Itajahay, Sa Catharina, Brazil
March 29. 1870.
My dear Sir
I have been detained from answering sooner your letter of Decbr. 1st, by an excursion into our primeval forests and afterwards by a severe illness of one of my daughters.1 And now, I must first express my cordial thanks for a copy of No 1 of “the Academy” and for the German translation of Wallace’s exceedingly interesting work on the Malay Archipelago.2 One of the points, which have interested me most in this work, is the dimorphism and mimicry of several butterflies.3 My attention having thus been called to our endemic butterflies, I have met also with several cases of close ressemblance of species belonging to distinct genera, which must probably be attributed to mimicry. There is, for instance a very common Pieris (1), and three or four other rather rare species, when seen from above, are more or less closely imitating the colours of this Pieris.—
I am much obliged for your account on Eschscholtzia;4 the influence of external conditions on the self-fertility of this 〈foot of page, probably containing diagram, excised〉 species is very curious; it is shown in a striking manner by a plant, which I had raised 1868 from your seeds and which only flowered 1869.—5 The other plants from the same seeds, which flowered the first year (1868) had retained self-fertility in a small degree; but this plant, which flowered only the second year, and had thus been exposed for a far longer time to our climate, proved perfectly self-sterile; it has been left uncovered, but growing at some distance from the other plants, which flowered at the same time, it produced by itself only a few very poor pods containing not even a single seed. Two flowers fertilised by pollen of a distinct plant yielded large pods, one of which contained 115 seeds.—
I have been much pleased by hearing from Alex. Agassiz, that he is now inclining to your views.6 I think very high of him as one of the most skilful and conscientious observers. His “Embryology of the Starfish” is a master-piece.—7
I gave you, in my last letter, some cases of plants, the first flowers of which had a larger number of petals or stamens than the later ones.8 I have since found, in a tree of C〈assia〉 multijuja, that the first flowers of 〈foot of page excised〉
His observations on mimicry in butterflies
and self-sterility in plants.
Please cite as
Darwin Correspondence Project, “Letter no. 7150,” accessed on 25 July 2016, http://www.darwinproject.ac.uk/DCP-LETT-7150