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Darwin Correspondence Project

To J. D. Hooker   [11 August 1861]

2. Hesketh Crescent | Torquay

Sunday

My dear Hooker

Could you spare me another spike of Apothecia & send it in tin box, or in oilsilk in wooden box1   I shd. wish one in very early bud, but one in full flower would be better than none?— Veitch has sent me a lot of magnificent Cattleyas all in full bloom;2 & as in some respects the pollinia are little modified, so the rostellum & means of fertilisation are simpler than in any other Orchid. In fact these flowers lead me to look at the rostellum as (in this the simplest case) part of the stigma very little modified & not distinct from the true stigma.—3 I want to see how the tissues are in the bud.—

The stigma secretes in Cattlya an enormous amount of viscid matter; I have said secrete, but it seems to me rather that the whole surface of the stigma deeply resolves itself into viscid matter; & this is all that the rostellum or upper part of the stigma does; & this viscid matter is forced by insects into the mouth of the anther & so withdraws the pollinia.—4 I certainly shd. very much like to see rostellum of Apothecia in early bud.

When I get home on Augst 28th. could you lend me Lindleys great work on Orchids to which he refers in Veg. Kingdom, as explaining nature of Parts;5 to my sorrow I fear I ought not to publish, without seeing what is known: I much fear that it is a very precious Book.—

Ever yours | C. Darwin

Footnotes

CD intended to write ‘Epithecia’, a synonym for the orchid genus Epidendrum. CD thanks Hooker for telling him about ‘Epithecia’ in the letter to J. D. Hooker, 13 [August 1861].
James Veitch Jr provided CD with species of exotic orchids (Orchids, pp. 158 n. and 214 n). He was a partner in James Veitch & Sons Exotic Nursery in Chelsea, which specialised in growing orchids and other rare plants.
CD described in detail the homology of the organs of orchids in the final chapter of Orchids, in which he argued that the rostellum had evolved from the third stigma of the flower. See Orchids, pp. 307–23.
CD illustrated the structure of this orchid in Orchids, p. 161.
The reference is to John Lindley’s statement in Lindley 1853, p. 174: ‘The general structure of Orchids, briefly embodied in the foregoing description, has been treated of at such length in the prefatory matter of the Illustrations of orchidaceous plants, that it is unnecessary to do more than refer the reader to that work.’ Lindley had provided an introduction and notes to the detailed drawings of orchids prepared by Franz Bauer, artist to Joseph Banks at the Royal Botanic Gardens, Kew (Bauer 1830–8).

Summary

Has found function of rostellum: modified stigma guarantees attachment of pollinia.

Letter details

Letter no.
DCP-LETT-3226
From
Charles Robert Darwin
To
Joseph Dalton Hooker
Sent from
Torquay
Source of text
DAR 115: : 108
Physical description
2pp

Please cite as

Darwin Correspondence Project, “Letter no. 3226,” accessed on 19 April 2019, http://www.darwinproject.ac.uk/DCP-LETT-3226

Also published in The Correspondence of Charles Darwin, vol. 9

letter