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Darwin Correspondence Project

To W. E. Darwin   [5 May 1863]1



My dear William

Hearty thanks for your letter about Anchusa.3 The case interests me much; but there have been several statements published of dimorphism in the Boragineæ.—4 I began to disbelieve,5 for all have 〈third of a page excised〉 which occurs in Thyme & mint;6 namely (1) form with long pistil & perfect anthers, (2) short-pistil & I think short stamen with imperfect anthers destitute of pollen: this second form bears seeds plentifully & must 〈be fertilised by form (1).—〉 〈third of a page excised〉 probably is like Primula;—but I shd. anticipate that form (1) would be perfectly fertile with own pollen & the second form would require pollen from nor I.— Do for Heaven-sake mark the place & get me seed in autumn; 〈four words excised〉 new case & would be well 〈third of a page excised〉 Down or go to Leith Hill, & we will write;7 but as I have not the compound microscope, I cannot compare pollen; & 2 or 3 flowers would suffice just that I might glance at flowers & satisfy my curiosity.8third of a page excised


The date is established by the relationship between this letter and the letters from W. E. Darwin, 4 May [1863] and 8 May [1863]. In 1863, 5 May was a Tuesday.
According to Emma Darwin’s diary (DAR 242), the Darwins stayed at Hartfield Grove in Hartfield, Sussex, the home of Charles Langton, between 27 April and 6 May 1863.
See letter from W. E. Darwin, 4 May [1863] and n. 1. The Anchusa was subsequently identified as Pulmonaria angustifolia.
CD’s sources of information on dimorphism in Boraginaceae included Lecoq 1854–8: 7, 428–68, and Vaucher 1841: 3, 441–66, in which Echium vulgare, Pulmonaria angustifolia, and Myosotis palustris (now called M. scorpioides) were identified as dimorphic. CD read Lecoq 1854–8 in December 1861 and Vaucher 1841 in March 1862 (see Correspondence vols. 9 and 10). There are heavily annotated copies of both works in the Darwin Library–CUL (see Marginalia 1: 488–95, 812–15).
CD’s own experiments with Echium vulgare, and several other members of the Boraginaceae, had led him to doubt suggestions that many species in this family exhibited heterostyly (see Correspondence vol. 10, letters to Asa Gray, 15 March [1862] and n. 11, and 9 August [1862] and n. 8). See also Forms of flowers, pp. 110–11.
Species of thyme and mint were taken by CD to be representative of a class of dimorphism that he later called ‘gyno-dioecism’, in which plants bear either hermaphrodite or female flowers (see Correspondence vol. 10, letter to Daniel Oliver, 12 [April 1862], and Forms of flowers, pp. 298–9). CD’s experimental notes on Mentha hirsuta, dated 28 August 1862, are in DAR 109: A3. Notes on Thymus, dated 29 May 1862 and 30 April 1863, are in DAR 109: A22 and A28. CD’s Experimental notebook also contains several entries on Thymus dated between 5 June 1861 and June 1863 (DAR 157a: 72). CD frequently referred back to these notes when observing cases of gyno-dioecism in other species (see DAR 109). CD may have indicated in the missing portion of the letter that the Anchusa (actually Pulmonaria angustifolia) might also be gyno-dioecious. See also letter to W. E. Darwin, [10 May 1863] and n. 3. CD’s experiments with Echium vulgare had established that some members of the Boraginaceae were gyno-dioecious (see Correspondence vol. 10, letter to Asa Gray, 9 August [1862]).
CD and Emma were undecided whether to go on from Hartfield to Leith Hill Place, near Dorking, Surrey (the home of Josiah Wedgwood III), or to return directly to Down (see letter from Charles and Emma Darwin to W. E. Darwin, [4 May 1863]). The Darwins stayed at Leith Hill Place from 6 to 13 May 1863 (see Emma Darwin’s diary (DAR 242)).
William sent the specimens on 8 May 1863 (see letter from W. E. Darwin, 8 May [1863]).


Discusses dimorphic plants.

Letter details

Letter no.
Charles Robert Darwin
William Erasmus Darwin
Sent from
Charles Langton, Hartfield
Source of text
DAR 210.6: 110

Please cite as

Darwin Correspondence Project, “Letter no. 4140,” accessed on 25 April 2019,

Also published in The Correspondence of Charles Darwin, vol. 11