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Darwin Correspondence Project

To Fritz Müller   25 March [1867]1

Down. | Bromley. | Kent. S.E.

March 25th.

My dear Sir

Your last letter received two days ago contained a multitude of curious facts about orchids.2 The case of the little orchid of which the long pedicelli performs such curious movements is very interesting. I once suspected that the pollen when partially dry acted best, but was quite unable to prove it; I daresay the final cause is what you suggest.3 Hildebrand of Bonn has just published a book which I have not read but which seems to me very good on the fertilisation of plants. I think it would perhaps interest you so I will get an additional copy & send it.4 Many thanks for your answer about the Maxillaria.5 The seeds of the Plumbago which you have sent are a treasure to me.6 I shall also be curious to see the two lobelias.7 The little bulbs of your semi-dioceus oxalis are growing well, except those of the flowers with semi foliaceous stamens & none of these grew; the others will not flower this year. Your Cordias have germinated well, but as I suppose they are trees I fear I never shall see them in flower.8 I have dispatched two copies of yr. paper on Climbing Plants as directed & will with pleasure send any others.9 Your brother (as I now know him to be) sent me some time ago some papers on mosses in which he has worked out with great care the variability of certain forms.10 I am working very hard at correcting proofs of my new book & the corrections are very heavy.11 I fear that neither you nor anyone will care much about this book which has cost me much more labour, I suspect, than it is worth.

I am extremely glad to hear that you like Häckel’s book;12 it is so long & the german rather difficult that I have been able to read only small portions. He seems to me a singularly clear thinker with great powers of methodical arrangement, but I have not met with much that seems actually new. I have, however, no right to judge. I liked the man so much that I do hope his book will be very successful.13

My dear Sir, believe me | yours very sincerely | Charles Darwin

P.S. What can be the cause of flowers like yr. Echites catching insects?14


The year is established by the relationship between this letter and the letter from Fritz Müller, 2 February 1867.
Müller had described the movement of the pedicel (now called stipe) of Ornithocephalus after the removal of the pollinium. He suggested that the initial movement was elastic, but that its final position was caused by hygroscopic movement, noting that it resumed its former position if put in water (see letter from Fritz Müller, 2 February 1867 and n. 11).
Friedrich Hildebrand had sent CD two copies of his book on plant sexuality, Hildebrand 1867a, one of which CD sent to Daniel Oliver (see letter to Friedrich Hildebrand, 20 March [1867] and nn. 2 and 4).
Müller had given CD an estimate of the number of seed capsules produced by Maxillaria tetragona (letter from Fritz Müller, 2 February 1867 and nn. 2 and 4).
Since Müller mentioned finding a dimorphic Plumbago in a letter of [2 November 1866] (Correspondence vol. 14), CD had been trying to obtain seeds of this genus from Joseph Dalton Hooker for his crossing experiments with dimorphic plants (see Correspondence vol. 14, letter to J. D. Hooker, 24 December [1866], and this volume, letter to J. D. Hooker, 29 January [1867]).
In a letter to J. D. Hooker of 24 [March 1867], CD reported that Müller had sent seeds of a climbing Lobelia, and of another kind which grew to ten feet in height.
CD had received bulbils of Oxalis sent by Müller in October 1866 and seeds of Cordia in early February 1867 (see Correspondence vol. 14, letter to Fritz Müller, [before 10 December 1866] and n. 2, and this volume, letter to Fritz Müller, 7 February [1867] and n. 4). Many species of Cordia, a member of the family Boraginaceae, are trees (Mabberley 1997).
The reference is to Müller’s paper on climbing plants, which had been sent to the Linnean Society by CD (F. Müller 1865; see also Correspondence vol. 13, letter from Fritz Müller, [12 and 31 August, and 10 October 1865]). Müller had probably given CD instructions for sending copies of the paper in his letter of 2 February 1867, of which only an incomplete copy is extant. In a letter to his brother, Hermann Müller, of 11 February 1867, Müller wrote that CD would send Hermann a copy of the paper (Möller ed. 1915–21, 2: 111).
Müller had mentioned his brother’s work on mosses in 1866 (see Correspondence vol. 14, letter from Fritz Müller, 2 August 1866). For the papers sent by Hermann Müller to CD, see the letter from Hermann Müller, 23 March 1867, n. 1.
CD had begun correcting proof-sheets of Variation at the beginning of March (see letter to W. B. Tegetmeier, 5 March [1867] and n. 2).
Müller’s comments on Ernst Haeckel’s Generelle Morphologie (Haeckel 1866) were evidently in a now missing part of his letter of 2 February 1867. In his letter to Hermann Müller of 11 February 1867, Müller wrote that he thought Haeckel’s book was very important, although he disagreed with many details and disliked Haeckel’s introduction of a large number of Greek neologisms (Möller ed. 1915–21, 2: 115–16).
Haeckel had visited CD in October 1866 (Correspondence vol. 14, letter from Ernst Haeckel, 19 October 1866).
Echites is a genus of the family Apocynaceae. Müller’s comments on Echites were evidently in a now missing part of his letter of 2 February 1867. In his letter to Hermann Müller of 11 February 1867, Müller wrote that the flower of an Echites growing in his garden had trapped a small bee by its proboscis, which was inserted between two anthers, and that the bee subsequently died (Möller ed. 1915–21, 2: 115). CD had earlier suggested that Müller should try to observe flowers that caught insects by their probosces, and mentioned that this occurred in some of the Apocyneae (a subfamily of Apocynaceae; see Correspondence vol. 14, letter to Fritz Müller, [9 and] 15 April [1866] and n. 9).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.

Haeckel, Ernst. 1866. Generelle Morphologie der Organismen. Allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie. 2 vols. Berlin: Georg Reimer.

Mabberley, David J. 1997. The plant-book. A portable dictionary of the vascular plants. 2d edition. Cambridge: Cambridge University Press.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Thanks for facts on orchids.

Friedrich Hildebrand’s new book on fertilisation of plants [Die Geschlechten-Vertheilung bei den Pflanzen (1867)].

CD correcting proofs of Variation.

FM likes Ernst Haeckel’s book [Generelle Morphologie (1866)].

Letter details

Letter no.
Charles Robert Darwin
Johann Friedrich Theodor (Fritz) Müller
Sent from
Source of text
The British Library (Loan MS 10 no 14)
Physical description
LS 4pp

Please cite as

Darwin Correspondence Project, “Letter no. 5458,” accessed on 29 May 2023,

Also published in The Correspondence of Charles Darwin, vol. 15