The Complete Work of Charles Darwin Online

RECORD: Müller, Hermann. 1878. Ophrys muscifera. Nature (27 June): 221. PC-Virginia-Orchids2dNature. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced courtesy of a private collection, Virginia.

This clipping is pinned to the inside front cover of Darwin's copy of Orchids 2d ed. (1877) with the Darwin library catalogue number on the top right corner of the title page: "S1 11 3b".

Darwin added the following passage to Orchids 2d ed. Revised 3d thousand (1882):

"Since the publication of the second edition in 1877, Hermann Müller has made the interesting observation* that the labellum of the Fly Ophrys is occasionally covered with drops of an excreted fluid, and in one instance he actually saw a fly (Sarcophaga, sp.) seated on the labellum and licking up the drops of fluid. The fly flew away without removing the pollinia; but if he had not been disturbed it is probable that he would have moved on and tried the sham nectaries of Sprengel, in which case he would have come in contact with the sticky disc of the pollen masses, and would thus have been able to effect the fertilisation of the next flower which he might visit.
* 'Nature,' 1878, p. 221, January 27. "

[page 221]

[annotation in Darwin's hand:] Nature / June 27. 1878 p. 221

Ophrys muscifera

On the afternoon of June 2, 1878, I observed some new facts, which, I think, are of importance in elucidating the hitherto mysterious fertilisation of the Fly-Orchis. In sunny weather and under normal conditions the labellum secretes fluid, and a broad central longitudinal stripe of its surface is covered with small drops. Of fifty fresh flowers I found the labellum in thirteen covered with drops, in twenty-five shining with adhering moisture, in twelve without any conspicuous trace of fluid. The two small shining projections on each side of the base of the labellum (the sham-nectaries of Sprengel) were quite di-y in all the flowers. In one flower I saw a fly (Sarcophaga sp.) sitting on the labellum and licking the drops. Its head was directed towards the base of the labellum. On my approaching it flew away before having reached the sham-nectaries, and the flower visited by it was found without pollen on the stigmas, and with both pollinia in their cells. Nevertheless, it is most probable that this fly, if not disturbed by my approach, would have stepped forward on the labellum, and, trying one of the sham-nectaries, would have removed one of the pollinia and perhaps transferred to the stigma of another stem, in the manner described by Charles Darwin ("Fertilisation of Orchids," p. 47).

For observing the fluid secreted by the labellum it may be essential to examine plants in their native habitats, not plucked ones.

Hermann Müller

Lippstadt

Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)