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Darwin Correspondence Project

To Daniel Oliver   29 [July 1862]1

Down Bromley Kent


Dear Oliver

Thanks for Orchids.—2 I liked to see the strange labellum of the Catasetum new to me.—3 Cycnoches is considerably different; there is a truly wretched sketch of the genus at the back of my orchid Book.—4 Do not take any more trouble about it: I only thought that as I had carefully examined C. ventricosum, I shd. like to see its male.—5

Yours very truly | C. Darwin

I care more for Dimorphism now than orchids, & I think it is a more important subject. To day I have been looking at Lythrum & have seen the three forms;—ie long-styled—mid-styled & short-styled:6 as each form has two sets of anthers, 18 different crosses are practicable within the limits of this one species!! As I ought to cross 10 of each, this would make 180 fertilisations & markings & counting of seeds. A nice job, Heaven knows whether my patience will last; but I shd. like to make out this wonderfully complex case—

I enclose stamps not to cheat Kew.—7


Dated by the relationship to the letter from Daniel Oliver, 28 July 1862.
There is a note in DAR 70: 98, dated 29 July 1862, that reads: a curious Catasetum sent me from Kew. with Lab[ellum] upwards, & thus is formed into a bucket with small oral orifice, by the base— lateral lobes meeting each other in front of column. The two antennae project in middle of the dark cavity & their tips can be seen through the oral orifice. Like a jar with narrowed in mouth.
CD had discovered that the specimen of which he provided a drawing in Orchids, p. 267, under the title ‘Section of the flower-bud of a Mormodes’, was actually Cycnoches ventricosum (see letter to Daniel Oliver, 24 July [1862] and n. 10; see also Orchids 2d ed., p. 223).
Having learned in December 1861 that Lythrum salicaria was trimorphic, CD had obtained plants for experiment from the Royal Botanic Gardens, Kew, and elsewhere (see letter to J. D. Hooker, 22 [March 1862], and DAR 27.2 (ser. 2): 1–7). There are a number of notes in DAR 27.2 recording the details of crossing experiments carried out by CD on this species in the summer of 1862; the earliest is dated 31 July 1862 (DAR 27.2 (ser. 2): 7). CD’s paper on the three forms in Lythrum (‘Three forms of Lythrum salicaria’) was read before the Linnean Society of London on 16 June 1864.
CD enclosed stamps worth 8d. to cover the cost of postage of the plant specimens sent with the letter from Daniel Oliver, 28 July 1862 (see CD’s annotation to that letter).


Cares more for dimorphism now than for orchids. Today saw the three forms of Lythrum, which means there should be 18 different practicable crosses.

Letter details

Letter no.
Charles Robert Darwin
Daniel Oliver
Sent from
Source of text
DAR 261.10: 55 (EH 88206038)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 3702,” accessed on 23 February 2019,

Also published in The Correspondence of Charles Darwin, vol. 10