Dated by the reference to CD’s having recently read a paper at a meeting of the Linnean Society (see n. 3, below), and by the relationship to the letter to J. D. Hooker, 9 [April 1862]. The first Monday following the meeting in question was 7 April 1862.
CD had been anxious to examine specimens of the orchid tribe Arethuseae, to which the genus Vanilla belongs, before completing Orchids, but had been unable to procure any living flowers (see Correspondence vol. 9, letters to J. D. Hooker, 27 July [1861] and 13 [August 1861], and this volume, letter to J. D. Hooker, 9 [April 1862]). See also Orchids, p. 269.