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Darwin Correspondence Project

To Francis Darwin   [c. December 1876]1

Thwaites Enumeratio Pl. Zeylan (Ceylon) (right title and date) p.p. 54 or 205. Sethia2

In one form the stamens are of equal length and in the other form alternately long and short— which is it?


The date is established by the relationship between this letter and the letter to Asa Gray, 20 December 1876.
In his taxonomic study, Enumeratio plantarum Zeylaniæ (Enumeration of the plants of Ceylon; Thwaites 1858–64, 5: 54, 205), George Henry Kendrick Thwaites used the terms stylosa and staminea to describe the different floral forms of Sethia obtusifolia (a synonym of Erythroxylum obtusifolium), Sethia acuminata (a synonym of Erythroxylum macrophyllum), and Limnanthemum indicum (a synonym of Nymphoides indica, water snowflake). In his description of Sethia obtusifolia, Thwaites remarked that although he initially considered that the two forms might be different species, he later concluded that they foreshadowed a ‘dioecious character’ (ibid., p. 54). CD included Thwaites’s description of Limnanthemum indicum and the species of Sethia in Forms of flowers, pp. 116, 122.


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

Thwaites, George Henry Kendrick. 1858–64. Enumeratio plantarum Zeylaniæ: an enumeration of Ceylon plants, with descriptions of the new and little-known genera and species, observations on their habits, uses, native names, etc. Assisted in the identification of the species and synonymy by J. D. Hooker. 5 pts. London: William Pamplin; Dulau & Co.


Asks for details of dimorphism in Sethia from Thwaites, Enumeratio plantarum Zeylaniae [1864]. [See Forms of flowers, p. 122.]

Letter details

Letter no.
Charles Robert Darwin
Francis Darwin
Sent from
Source of text
DAR 153: 28
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10762,” accessed on 27 February 2021,

Also published in The Correspondence of Charles Darwin, vol. 24