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Darwin Correspondence Project

To W. K. Bridgman   21 January [1869]1

Down. | Bromley | Kent S.E.

Jan 21.

Dear Sir.

Mr Jeffreys has forwarded your letter which has interested me, as I remember speculating some few years ago, whether Aucuba was fertilised by the wind or insects.2

I do not remember whether the coincidence of the secretion of nectar & the opening of the Anthers has ever been observed and it would take a long search to discover— But it is a pretty fact which ought on some fitting occasion to be published   I rather doubt whether it will prove a general rule— So many flowers open their anthers before the Corolla even expands— The following fact has some bearing on your observation:—I have observed (& I think recorded dates) that during many days the flowers of the common Polygala—Linaria cymballaria and some of the smaller clovers may all be fully expanded and not a bee will visit them, and then suddenly swarms of bees will visit the flowers, which marks I believe the first secretion of nectar.—3

Again the stipules of the common Vetch secrete nectar (of no service for fertilisation) whilst the sun shines, & crowds of Hive Bees suck the stipules; the sun is obscured & in a very short time not a bee can be seen; again there is sunshine and again bees.—4 I observed this several times on the same day & wondered how the news spread so rapidly through the Hive, but I suppose that all the bees knew the fact, & did not need to communicate it.—

I wish I could have answered your query more precisely & I beg leave to remain— | Dear Sir. | Yours very faithfully. | Ch. Darwin.

Footnotes

The year is established by the relationship between this letter and the letter from W. K. Bridgman, 23 January 1869.
See letter from W. K. Bridgman to J. G. Jeffreys, [before 21 January 1869].
In Cross and self fertilisation, p. 422, CD reported on the sudden increase in the activity of bees visiting certain flowers, including Linaria cymbalaria (now Cymbalaria muralis, ivy-leaved toadflax) and Polygala vulgaris (common milkwort), and hypothesised that the secretion of nectar might be accompanied by ‘some odour’ alerting bees to its presence.
In Cross and self fertilisation, pp. 403 and 422, CD discussed the excretion of fluid on the stipules of Vicia sativa (vetch) and its relation to the amount of sunshine present.

Bibliography

Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

Summary

Discusses fertilisation of Aucuba and Polygala.

Letter details

Letter no.
DCP-LETT-6565
From
Charles Robert Darwin
To
William Kencely Bridgman
Sent from
Down
Source of text
DAR 143: 146
Physical description
2pp

Please cite as

Darwin Correspondence Project, “Letter no. 6565,” accessed on 26 September 2021, https://www.darwinproject.ac.uk/letter/DCP-LETT-6565.xml

Also published in The Correspondence of Charles Darwin, vol. 17

letter