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Darwin Correspondence Project

To L. A. Errera   4 October 1877

Down, | Beckenham, Kent.

Oct 4th 1877

Dear Sir,

I have now read your M.S.1 The whole has interested me greatly & is very clearly written   I wish that I had used some such terms as ‘autogamy’ ‘xenogamy’ &c.2 I entirely agree with you on the a priori probability of geitonogamy being more advantageous than autogamy; & I cannot remember having ever expressed a belief that autogamy as a general rule was better than geitonogamy; but the cases recorded by me seem too strong not to make me suspect that there was some unknown advantage in autogamy. In one place I insert the caution “if this be really the case”, which you quote.3 I shall be very glad to be proved to be altogether in error on this point.

Accept my thanks for pointing out the bad erratum at p 301.4 I hope that you will experimentize on inconspicuous flowers; if I were not too old & too much occupied I would do so myself.5

Finally let me thank you for the kind manner in which you refer to my work & with cordial good wishes for your success, I remain | dear Sir | Yours faithfully | Charles Darwin


Errera, a doctoral student in botany at the Free University in Brussels, had sent CD a section of an article on heterostyled plants that he had written with Gustave Gevaert (see letters from L. A. Errera, 15 September 1877 and 30 September 1877). The paper was published in 1878 (Errera and Gevaert 1878); there is a copy in the Darwin Pamphlet Collection–CUL.
Errera had used the terms autogamy to denote self-pollination, geitonogamy to denote pollination by the pollen of a different flower on the same individual, and xenogamy to denote the crossing of different individuals (see letter from L. A. Errera, 30 September 1877 and nn. 3 and 4).
CD used this phrase twice in relation to the advantages of self-fertilisation; see Cross and self fertilisation, pp. 352 and 386.
It is possible that the amanuensis wrote ‘301’ in error. In the manuscript sent to CD, the authors probably pointed out that in Forms of flowers, p. 307, the statement that the corolla was ‘rather larger in the females’ must have been a misprint because the text should have stated that the corolla in females was smaller. The same point was later mentioned in Errera and Gevaert 1878, p. 154 n. 4. The correction was not made in Forms of flowers 2d ed.
Inconspicuous flowers were thought to favour self-fertilisation because they were too small to attract the attention of insects. CD, however, believed that plants bearing inconspicuous flowers must cross from time to time otherwise the flowers would have become cleistogamic; in Cross and self fertilisation, p. 387, he expressed his regret that he had not carried out experiments to test this view.


Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

Forms of flowers 2d ed.: The different forms of flowers on plants of the same species. 2d edition. By Charles Darwin. London: John Murray. 1880.

Forms of flowers: The different forms of flowers on plants of the same species. By Charles Darwin. London: John Murray. 1877.


Approves terms used in LAE’s manuscript. Discusses relative advantages of self-fertilisation and cross-fertilisation.

Thanks LAE for pointing out erratum [in Cross and self-fertilisation].

Letter details

Letter no.
Charles Robert Darwin
Léo Abram Errera
Sent from
OC 4 77
Source of text
American Philosophical Society (Mss.B.D25.523)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11166,” accessed on 27 November 2020,