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Darwin Correspondence Project

To Fritz Müller   4 July 1881

Down, | Beckenham, Kent. | (Railway Station | Orpington. S.E.R.) [Glenridding House, Patterdale.]

July 4th. 1881.

My dear Sir

Your kindness is unbounded, & I cannot tell you how much your last letter (May 31st) has interested me.1 I have piles of notes about the effects of water resting on leaves, & their movements (as I supposed) to shake off the drops.2 But I have not looked over these notes for a long time, & had come to think, that perhaps my notion was mere fancy, but I had intended to begin experimenting, as soon as I returned home; & now with your invaluable letter about the position of the leaves of various plants during rain, (I have one analogous case with Acacia from S. Africa)3 I shall be stimulated to work in earnest.—

Very many thanks for the seeds which shall be sown. As soon as I saw Schizolobium, I inferred the structure was for distribution, but I could not imagine what its homologous nature was: I will show these seeds to Sir J. Lubbock, who is greatly interested in the subject.—4

I wrote a few days ago to you about your books.—5

I wrote also to Dr. Breitenbach & suggested to him to observe the flowers of the Melastomaceæ; but if you felt inclined to take up the subject, you wd. do it incomparably better & make out the meaning of the two sets of anthers.6 I am trying to raise some Melastomaceous plants, but nothing can be well made out about the fertilisation of a plant, except in its native country.—

I shd like to hear whether the leaves of the Schizolobium, & of the Acacia of Oxalis sepium & of Ph. consanguineus & Phyllanthus Sp. III. (all of which move downwards during rain) are protected by a waxy secretion,— that is if when immersed under water they shine like silver, & are not wetted when soon withdrawn.

I have written in a hurry as we return home today, & I have many things to arrange7 | with hearty thanks, My dear Sir | Yours very sincerely | Ch. Darwin


CD first suggested that leaf movement might shake off water drops in his letter to T. H. Farrer, 14 August 1873 (Correspondence vol. 21). His notes on experiments in this regard on Oxalis sensitiva (a synonym of Biophytum sensitivum) are in DAR 68: 133–6; extensive notes on the effects of water on plants with sensitive leaves such as Mimosa sp. and Desmodium gyrans (a synonym of Codariocalyx motorius), made between 1873 and 1882, are in DAR 209.
CD had observed the application of water to plants of Acacia lophantha (a synonym of Paraserianthes lophantha, plume albizia; the species is an Australian native, but was introduced to South Africa by British colonists early in the nineteenth century). CD’s notes, dated between 25 and 28 December 1877, are in DAR 209.12: 27–8.
Müller had evidently sent seeds, including some of Schizolobium parahyba (Brazilian firetree); CD’s notes on movement in the leaflets, dated between 12 and 13 September 1881, are in DAR 209.12: 174. The seed-pods are compressed oblong-cuneate in shape, dehiscing into two halves and liberating the single apical seed, which remains enclosed in the similar-shaped papery envelope of endocarp resembling a wing. The seeds are wind-dispersed.
CD had offered to pay to replace books that Müller had lost in a flood (see letter to Fritz Müller, 21 June 1881).
See letter to Wilhelm Breitenbach, 20 [June] 1881. Melastomaceae (a synonym of Melastomataceae) is a family of flowering plants found mostly in the tropics; for more on CD’s research on plants in this family, see letter to Fritz Müller, 20 March 1881 and nn. 2 and 6.
The Darwins spent the night of 4 July at Penrith before returning to Down on 5 July (see letter to G. J. Romanes, 4 July [1881] and n. 2).


Movement of plants to shake off water: FM’s invaluable observations.

Inquires about "bloom" on leaves.

Fertilisation of Melastomataceae, roles of the two sets of anthers.

Letter details

Letter no.
Charles Robert Darwin
Johann Friedrich Theodor (Fritz) Müller
Sent from
Source of text
The British Library (Loan MS 10 no 53)
Physical description
ALS 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 13233,” accessed on 27 March 2023,