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Darwin Correspondence Project

To Linnean Society, President and Council   [10 May 1869]1

Report on Mr Spruce’s paper.2

I feel considerable difficulty in expressing an opinion on this paper, from not knowing how few Botanists have generally supposed that the sacs &c are independent growths in the plants. If this be so, as I suppose from the terms used, it seems to me highly desirable that the facts, here recorded and observed by a naturalist on the spot, should be published; more especially as Mr Spruce shews under what conditions and contingencies the sacs are formed. The presence of sacs &c in plants belonging to various widely different orders, is also a very interesting circumstance. But the point which Mr Spruce seems to think the most important, namely that the sacs in the course of ages have become inherited, is manifestly very improbable, and appears to rest on hardly any evidence. The evidence advanced is, firstly, the generality of the presence of sacs, accompanied however by an almost equal generality in the presence of ants, in certain species; and secondly, that he saw in one case (p. 6) sacs beginning to be formed long before any ants had visited the plant. But it seems to me not a little doubtful that it could have been positively ascertained that ants had never visited such plants; and Dr Hooker informs me that none of the Melastomas have ever produced sacs in the hothouses at Kew.3 I would suggest that the paper should be printed, with two or three illustrations, on condition that the author is willing to alter the title and to strike out several short passages (marked with pencil) in which the sacs &c. are spoken of as being inherited. The author might of course state that he had been led to suspect that these structures are now inherited, and this might lead to further investigations; but to speak positively on the subject of inheritance without much fuller evidence would be in my opinion injurious to the reputation of the author and of the Society.

To the President | & Council of the | Linnean Socy.


The date is established by the relationship between this letter and the letter to George Bentham, 10 May [1869].
Richard Spruce had sent CD a paper on the modification of plant structure by ants for submission to the Linnean Society (see letter from Richard Spruce, [before 1 April 1869]. For a transcription of the paper, which was not published by the society, and an account of events surrounding its submission, see Spruce 1908, 2: 384–412. There is a draft of this report in CD’s hand in DAR 96: 75.
Joseph Dalton Hooker was director of the Royal Botanic Gardens, Kew. No correspondence between CD and Hooker on this subject has been found, but Hooker visited Down on 25 April 1869 (Emma Darwin’s diary (DAR 242)).


Spruce, Richard. 1908. Notes of a botanist on the Amazon & Andes, being records of travel … during the years 1849–1864. Edited by Alfred Russel Wallace. 2 vols. London: Macmillan and Co.


Referee report on paper by Richard Spruce on sacs in Melastoma [see 6690]. CD says RS’s suggestions that sacs are inherited is not supported and should be deleted.

Letter details

Letter no.
Charles Robert Darwin
Linnean Society, President and council
Sent from
Source of text
The Linnean Society of London
Physical description
2pp damaged & Adraft 2pp

Please cite as

Darwin Correspondence Project, “Letter no. 6722,” accessed on 22 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 17