To H. G. Bronn1 11 July 1862
Down Bromley Kent
Dear & Honoured Sir
I am very sorry to be troublesome, but I hope you will insert following note to “Mormodes”* p. 265. (7 lines from bottom) instead of the short one before sent.2
I have now examined perfect flowers of this orchid. It is the Cynoches ventricosum.3 I have erred to a certain extent in my conjectures on the action of the parts. The sensitive point lies in some part of the filament of the anther, between two little leaf-like appendages on the summit of the column. The movement of the pollinium is nearly the same as in Mormodes ignea, & the anther is torn off. But the power of ejection is more feeble; & the viscid surface of the disc after the movement projects at right angles to the anther. There can be no doubt that insects either alight on, or touch, the anther or end of the column, which hangs downwards, & then the disc is flirted out, & sticks probably to their heads; but the whole pollinium is not shot to a distance as in Catasetum. In about quarter of an hour the pedicel of the pollinium slowly straightens itself, as in the case of Mormodes ignea.
p. 324 (3 lines from bottom) Orchids*
[asterisk]I now find that in several, perhaps in most of the Arethuseæ,—a tribe which as stated I had until lately no opportunity of examining,—the pollen-grains are simple, that is are not compounded of three or four granules.4
Dear sir | Yours truly obliged | Ch. Darwin
Sends additional notes.
Please cite as
Darwin Correspondence Project, “Letter no. 3652,” accessed on 24 August 2016, http://www.darwinproject.ac.uk/DCP-LETT-3652