Ɛpsilon

To Hermann Müller1   [9 October 1867]2

[Down.]

Ihre Beobachtungen über Orchideen sind ausgezeichnet, besonders die Bestätigung in Bezug auf Cypripedium, und dies sollte sicherlich eines Tages veröffenlicht werden.3 Es ist fast ein so schönes Beispiel wie das von Coryanthes mit ihrer mit Wasser gefüllten Lippe, wie es Crüger beschrieben hat4   Sie sprechen von dem Geruch des Cypripedium, aber bei einigen ausländischen Arten sah ich kleine Flüssigkeitströpfchen an den Haaren innerhalb der Lippe, welche ein wahrscheinlicheres Auziehungsmittel bilden. Sie haben Erfolg gehabt, in Dingen, die mir in früheren Jahren der Beobachtung fehlschlungen, z. B indem Sie ein Insekt an der Ophrys sahen, aber ich kann mich nicht davon überzeugen, dass die Schnäbelchen (rostella) den Anziehungspunkt bildeten.5 Das Insekt muss, wie ich denke, sehr durstig gewesen sein; ich selbst habe eine Wespe gesehen, welche sich am Auge eines Mannes niederliess und die Thränen sog […]

1
For a translation of the German of the printed source, see Appendix I.
2
The date is given in the printed source (see Krause 1884, p. 18).
3
In an earlier, now missing letter, Müller had suggested that bees were poisoned by the odour of Cypripedium calceolus (lady’s slipper; see this volume, Supplement, letter to Hermann Müller, 16 August [1867] and n. 6). He evidently wrote to CD confirming CD’s observation that the inward curvature of the labellum prevented insects from exiting the flower as they had entered, that is, by pushing open the bladder-like labellum.
4
Hermann Crüger had described the ‘bucket’ of fluid in Coryanthes macrantha (bucket orchid) in Crüger 1864, p. 130.
5
Most orchids possess a rostellum, a beak-like structure that separates the anthers from the stigma and secretes a sticky stigmatic fluid, termed by CD the ‘viscid disc’ (see Orchids, pp. 6–7), and in modern terminology the viscidium. Müller had probably suggested that this fluid attracted insects.

To Hermann Müller1   [9 October 1867]2

[Down.]

Your observations on orchids are excellent, especially the confirmation regarding Cypripedium, and this surely ought to be published one day.3 It is almost as beautiful an example as that of Coryanthes with its water-filled labellum, as Crüger has described.4 You mention the odour of Cypripedium, but in some foreign species, I saw small droplets on the hairs inside the labellum, which probably serve as a means of attraction. You have succeeded in things that I failed at in former years, e.g. you saw an insect on Ophrys, but I cannot convince myself that the rostellum (rostella) is the site of attraction.5 The insect must, I think, have been very thirsty; I myself have seen a wasp, which landed on a man’s eye and drank the tears […]

1
For a transcription of the German of the printed source, see Transcript.
2
The date is given in the printed source (see Krause 1884, p. 18).
3
In an earlier, now missing letter, Müller had suggested that bees were poisoned by the odour of Cypripedium calceolus (lady’s slipper; see this volume, Supplement, letter to Hermann Müller, 16 August [1867] and n. 6). He evidently wrote to CD confirming CD’s observation that the inward curvature of the labellum prevented insects from exiting the flower as they had entered, that is, by pushing open the bladder-like labellum.
4
Hermann Crüger had described the ‘bucket’ of fluid in Coryanthes macrantha (bucket orchid) in Crüger 1864, p. 130.
5
Most orchids possess a rostellum, a beak-like structure that separates the anthers from the stigma and secretes a sticky stigmatic fluid, termed by CD the ‘viscid disc’ (see Orchids, pp. 6–7), and in modern terminology the viscidium. Müller had probably suggested that this fluid attracted insects.

Please cite as “DCP-LETT-5620F,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-5620F