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Darwin Correspondence Project

To J. D. Hooker   17 June [1860]1

Down Bromley Kent

June 17th

My dear Hooker

I have reread your paper on Listera2 & have been looking as specimens, & have hardly ever been more amused. In Neottia nidus-avis, the rostellum is thicker, & the summit is so wonderfully sensitive, that a touch from a child’s hair, not held close to point was sufficient to cause the ejection of the fluid!! & what delighted me was that this fluid sets so quick, becoming slightly opake, that in 2 seconds or even less when the touching object was withdrawn, a mass of pollen was withdrawn with it.—   I send the hair in quil, with which I touched top of rostellum of Neottia, & almost instantly withdrew it & you will see (if you think it worth cutting open quil) pollen glued to end. So that insect by this wondrous contrivance would be sure to carry pollen from flower to flower.—   The same thing happens with Listera, but in this case whole pollen-mass in a flower only lately expanded, is with drawn.—

I cannot believe from what I have seen that pollen mass can be ejected by the ejection of fluid matter; for during first second it is not very viscid. A more important difference is that in Neottia pollen is shed in bud & is cast irregularly on to the rostellum & does not adhere to it till the fluid is ejected; & the adhesion is indefinite ie to any point of the pollen-masses, & not to the apices of the pollen-mass as in Listera.— I suspect, from one case that I saw that pollen-masses are ejected from anthers of Listera with force, before & independently of ejection of fluid.—   I can see that this viscid fluid is analogous to sticky gland of orchis, but it seems to me, in my ignorance, that in Listera the opposite end of pollen-masses are attached, to what is the case in Orchis.—3

In Cephalanthera grandiflora the pollen-masses are shed in bud & stand close in two friable column close to upper edge of stigma; & this upper edge, (which I presume answers to rostellum) whilst in bud-state, ejects fluid (without touch) on each side & glues the pollen-masses there; as the rim with the glue turns reddish, it is probably homologous to the viscid secretion of Listera & Neottia.—4 I am sure I do not know whether you care enough about Listera to hear this about Neottia.

Yours affect | C. Darwin

It requires no sort of answer.

I can see externally to loculi in rostellum of Neottia.—

I have got good facts about moths & orchids.— good evidence thank Heaven of pollen-masses of Bee Orchis adhering to proboscis of moth; & one moth sent me with 13 pollen-masses of some orchis adhering to its proboscis, rendering it quite arborescent.—5 I could recognise pollen-mass of Butterfly-orchis on 2 other moths.—

Footnotes

Dated by the relationship to the letters to the Gardeners’ Chronicle, [4–5 June 1860], and to J. D. Hooker, 12 [June 1860].
Hooker 1854b.
CD described the pollen-masses of Listera and Neottia in Orchids, pp. 152–5. He wrote: ‘I found in 1860 so many flowers exploded, with a bead of the purplish hardened cement attached to the crest of the rostellum and to the unremoved pollinia, that I suspect that it does explode, after a time, spontaneously, without the excitement of a touch.’ (Orchids, p. 153).
CD eventually considered the mechanisms for cross-fertilisation in Neottia to be intermediate between those of Epipactis and Cephalanthera (Orchids, p. 155).
See letter to J. D. Hooker, 12 [June 1860], and letter from Frederick Bond, [16? June 1860]. The specimen was probably one of several moths that Bond sent to CD having large numbers of pollinia attached to their mouth-parts (see Orchids, p. 35).

Bibliography

Orchids: On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. By Charles Darwin. London: John Murray. 1862.

Summary

Has reread JDH’s paper ["On the functions of the rostellum of Listera ovata", Philos. Trans. R. Soc. Lond. 144 (1854): 259–64].

Letter details

Letter no.
DCP-LETT-1571
From
Charles Robert Darwin
To
Joseph Dalton Hooker
Sent from
Down
Source of text
DAR 261.10: 68 (EH 88206051)
Physical description
4pp

Please cite as

Darwin Correspondence Project, “Letter no. 1571,” accessed on 15 December 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-1571.xml

Also published in The Correspondence of Charles Darwin, vol. 8

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