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Darwin Correspondence Project

To Asa Gray   30 May [1875]1

Down, | Beckenham, Kent. | Railway Station | Orpington. S.E.R.

May 30th

My dear Gray

Would you be so kind as to get & send me this summer a packet of seeds of Nessæa verticillata. I want to raise seedlings from illegitimate unions to see if the seedlings are sterile like true Hybrids & like the illeg. offspring of Lythrum; for the fact seems to me all important.—2

Ever yours | C. Darwin


The year is established by the printed stationery, which is of a sort used by CD from 18 November 1874, and by CD’s statement in February 1875 that he intended to carry out more research on dimorphic and trimorphic plants (see n. 2, below).
Gray had sent CD Nesaea seeds in 1862 (see Correspondence vol. 10, letter from Asa Gray, 27 October 1862). Nesaea verticillata (a synonym of Decodon verticillatus) is the swamp loosestrife, native to eastern North America. CD had first experimented on Lythrum salicaria (purple loosestrife) in 1862 when investigating the connection between dimorphism and sterility, and had published the results in ‘Three forms of Lythrum salicaria’ and ‘Illegitimate offspring of dimorphic and trimorphic plants’ (see Correspondence vol. 10). He was considering carrying out further research and revising these papers for inclusion in Cross and self fertilisation (see letter to J. V. Carus, 7 February 1875). The reworked papers eventually appeared as part of Forms of flowers, but there is no discussion of Nesaea verticillata beyond what was originally included in ‘Three forms of Lythrum salicaria’.


Wants seeds of Nesaea verticillata for crossing experiments to see whether seedlings from "illegitimate unions" are sterile like true hybrids.

Letter details

Letter no.
Charles Robert Darwin
Asa Gray
Sent from
Source of text
Archives of the Gray Herbarium, Harvard University (121)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10002,” accessed on 17 August 2019,

Also published in The Correspondence of Charles Darwin, vol. 23