My dear Sir

I have been detained from answering sooner your letter of Decbr. 1^st, 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 N^o 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⟩⁠