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Darwin Correspondence Project

From J. S. Henslow   21 November 1840

Hitcham Bildeston | Suffolk

21 Nov 1840

My dear Darwin,

I have examined the flowers of your Thyme— The Anthers are abortive—which is not uncommon in more than one species of the Genus— In nearly the whole Order,1 one stamen out of 5 is constantly suppressed, either entirely, or there remains merely a rudiment of a filament— The suppression of the 5 Anthers shews a tendency in the present species towards becoming diœcious, but I don’t known whether the pistil is ever suppressed whilst the Anthers remain perfect—2

I expect to be in town on Decr. 7, when I take my Eldest Dr. 3 to St Albans, & bring back Leonard—4 I shall probably have to give a lecture to the Agriculturists on the 10th—as some of them seem to wish to hear something about Diseases in Corn, & a few drawings explanatory of my forthcoming report5 may serve to assist their conceptions— I am glad to find that you are at length back, & will certainly call—but I will not think of accepting any hospitality—for I feel that it would be wrong to risk a chance of bringing on a relapse—6

With Kindest remembrances to Mrs D. | Ever yours sincerely | J. S. Henslow

CD annotations

crossed ink
At head of letter: ‘Effect of Autumnal Flowering’7 ink


This letter was kept with materials used in writing Forms of flowers (DAR 109: 86). By the time of that publication (1877), CD had decided that thyme is gyno-dioecious, i.e., has both hermaphrodite and female forms (pp. 298–303). The flower Henslow examined was a female, with aborted stamens, of the lemon-thyme (Thymus serpyllum var citriodorus). CD may be referring to the same plant in a note made on 1 June 1841: ‘Maer Examined the Lemon-thyme.— equally abortive as it was in autumn: … As we see in Hybrids that although anthers *nor filaments [interl] shrivel, yet stigma does not, so we may feel somewhat *but little [interl] less surprised at Henslow’s remark that pistil does not become abortive.’ (Torn-apart notebook : 99 (DAR 109: 16)).
Frances Henslow.
Leonard Ramsay Henslow.
Henslow 1841.
CD had returned to London on 14 November (‘Journal’; Correspondence vol. 2, Appendix II), having been ill a good part of the time since August at Maer.
This note probably dates from the summer of 1841, when CD went back to Maer and again found the abortive form (see n. 2, above). It may reflect a view of variation in nature which CD particularly stressed in the 1840s: variation occurs rarely and only when conditions change (see the sketch of 1842 in Foundations). Thus flowering under autumnal conditions induces a change in the reproductive system.


Reports on abortive anthers in flowers of thyme sent by CD.

Letter details

Letter no.
John Stevens Henslow
Charles Robert Darwin
Sent from
Source of text
DAR 109: A86
Physical description
2pp †

Please cite as

Darwin Correspondence Project, “Letter no. 582,” accessed on 17 August 2017,

Also published in The Correspondence of Charles Darwin, vol. 2