To A. G. More   19 July [1861]1

2. Hesketh Crescent | Torquay

July 19th

My dear Sir

Very sincere thanks for the E. palustris which will be very useful, as I have 2 or 3 doubtful points to examine.—2 I am greatly obliged for your patience in watching the flowers;3 I know from experience it is tedious work. From analogy I shd. doubt moths being the visitants.—4 The irritability must be from what you say a false scent—yet a drop of Chloroform certainly caused first a slight movement forwards & then backward; but this, I now infer was mechanical from endosmose or exosmose.5 Were your observations made in sunshine? I can see it would be very difficult to detect any movement owing to great flexibility and elasticity of the part.—

Hearty thanks for the experiment of cutting off the distal portion of the Labellum;6 your friend could see whether the pods of these flowers swelled in course of few weeks as well as those of the unmutilated flowers; but it would be well to open them to look for seeds.—7 My notion is that the springing back of the elastic labellum leads the insects to crawl out of the upper part of the flower and not backwards over the labellum.— I am sure for removing the pollinia, the rostellum has to be brushed upwards and outwards.8

Again believe me | My dear Sir | Yours sincerely obliged | Charles Darwin

1
This letter was first published in Correspondence vol. 9, transcribed from a copy on which the year is recorded (DAR 146: 400).
3
CD thanked More for repeatedly sending him specimens of the marsh orchis, Epipactis palustris, in Orchids, p. 95 n. More had apparently observed that when flies visited this orchid, their weight caused part of the labellum to become greatly depressed (see Orchids, p. 99).
4
CD discovered after the publication of Orchids that hive-bees were ‘the chief agents in fertilisation’ of this orchid (see Orchids 2d ed., p. 99).
5
These terms denote the passage of fluid inwards and outwards, respectively, through a porous membrane (OED).
6
CD had asked More to carry out this experiment (letter to A. G. More, 7 July [1861]).
7
CD reported the results in Orchids, pp. 101–2 n.: As it is quite possible that I may have overrated the importance of the peculiar structure of the labellum, I asked Mr. A. G. More to remove the distal half of the labellum from some flowers before they had expanded, but I was too late in my application. He was able to try only two flowers, which were situated near the summit of the spike. These flowers formed seed-capsules, which were certainly small; but this may have been owing to their position. Unfortunately also these capsules shed most of their seed in being sent to me; so that I could not ascertain whether the seeds were well formed. Of the few seeds which did remain within these two capsules many were shrivelled and bad.
8
In Orchids, pp. 99–100, CD provided a full account of how he arrived at this understanding of the pollinating mechanism of Epipactis palustris.

Manuscript Alterations and Comments

1.00 moths] after del ‘it be’
1.00 forwards] interl
2.00 flowers;] semi-colon over point
2.00 but it would] ‘but’ over dash
2.00 but … seeds.—] added
2.00 springing … labellum] interl above del ‘elasticity’
2.00 crawl out] ‘out’ after del illeg

Please cite as “DCP-LETT-3213,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-3213