From Hermann Müller   2 April 1877

Lippstadt,

April 2, 1877.

My dear Sir

Your agreement to my suggestions and criticisms on your work is a great pleasure to me, and I am very much obliged to you for your advices regarding the experiments to be made with Viola tricolor and the other plants with two kinds of flowers. Four years ago I began such experiments, but unforeseen difficulties frustrated them.1 Rhinanthus and Euphrasia being parasites during their youth, I did not succeed in getting seedlings from them.2 The small-flowered Viola tricolor commonly is self-fertilised before opening its flowers. Supposing that pollen from a distinct stock would be prepotent, I crossed many of its flowers; but my experiments were interrupted before being finished by my absence during the vacancies.

Induced by your letter I will collect as soon as possible and sow a large number of seeds of the small flowered V. tricolor in order to discover whether both forms appear amongst the seedlings. I will also, with greater perseverance, repeat the cross and self fertilisation of the large and small flowered form of Viola tricolor and perhaps of Lysimachia vulgaris and Calamintha alpina.3

My brother lately in the highlands (Campos) of South Brazil has discovered a white flowered Viola species with subterraneous cleistogameous flowers. He says in his last letter to me, that he has in view to collect seeds of both kinds of flowers in order to experiment on them.4

My brothers paper on the neuration of the wings of the two sexes of Lepidoptera has not yet been printed. I will send it to you as soon as I have received it.5

In the next numbers of Kosmos two essays of mine will appear, in which I have attempted to explain some pecularities of entomophilous flowers by what you have statet on the effects of cross and self-fertilisation.6

With the highest respect | yours very sincerely | H. Müller

CD annotations

3.1 My brother … on them. 3.4] double scored pencil and red crayon
1
Neither Müller’s letter nor CD’s reply have been found. Müller had received copies of Cross and self fertilisation (Correspondence vol. 24, Appendix III) and Orchids 2d ed. (this volume, Appendix IV); his suggestions probably related to Cross and self fertilisation, which he had received in December 1876 (see Correspondence vol. 24, letter from Hermann Müller, 6 December 1876). In his book Befruchtung der Blumen durch Insekten (Fertilisation of flowers through insect agency; H. Müller 1873, p. 145), Müller had described insect visitors to the large open flowers of Viola tricolor. He discussed his continuing observations of insects that visited V. tricolor and the self-fertilising form of the species in letters of 19 May 1873 and 10 June 1873 (Correspondence vol. 21).
2
Rhinanthus or rattle is a genus of hemiparasitic plants, that is, it draws some nutrition from the roots of grasses, but also photosynthesises. All species of Euphrasia (the genus of eyebright) are also hemiparasitic on grasses.
3
Lysimachia vulgaris is garden loosestrife; Calamintha alpina is a synonym of Clinopodium alpinum, alpine calamint.
4
CD reported Fritz Müller’s observation in Forms of flowers, p. 318. Some of Fritz Müller’s letters to Hermann are reproduced in Fritz Müller. Werke, Briefe und Leben (Möller ed. 1915–21), but the letter mentioned is not included.
5
Fritz Müller’s paper ‘Beobachtungen an brasilianischen Schmetterlingen’ (Observations on Brazilian butterflies; Fritz Müller 1877a) appeared in three parts in Kosmos between September and December 1877. The first section of the first part, ‘Die Flügeladern der Schmetterlingspuppen’ (Wing neuration of butterfly pupae) appeared in the September issue.
6
Hermann Müller’s papers ‘Darwin’s Werk “Ueber die Wirkungen der Kreuzung und Selbstbefruchtung im Pflanzenreich” und seine Bedeutung für unsere Verständniß der Blumenwelt’ (Darwin’s work ‘On the effects of cross and self fertilisation in the plant kingdom’ and its meaning for our understanding of the world of flowers; H. Müller 1877a) and ‘Ueber den Ursprung der Blumen’ (On the origin of flowers; H. Müller 1877b) appeared in the April and May issues of Kosmos.

Please cite as “DCP-LETT-10921,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10921