with their much stronger ones, could penetrate with ease the soft inner membrane of the nectaries of the above-named Orchids. Dr. H. Müller is also convinced[1] that insects puncture the thickened bases of the standard petals of the Laburnum,[2] and perhaps the petals of some other flowers, so as to obtain the included fluid.
The various kinds of bees which I saw visiting the flowers of Orchis morio remained for some time with their proboscides inserted into the dry nectaries, and I distinctly saw this organ in constant movement. I observed the same fact with Empis in the case of O. maculata; and on afterwards opening several of the nectaries, I occasionally detected minute brown specks, due as I believe to the punctures made some time before by these flies. Dr. H. Müller, who has often watched bees at work on several species of Orchis, the nectaries of which do not contain any free nectar, fully accepts my view.[3] On the other hand, Delpino still maintains that Sprengel is right, and that insects are continually deceived by the presence of a nectary, though this contains no nectar.[4] His belief is founded chiefly on a statement by Sprengel that insects soon find out that it is of no use to visit the nectaries of these orchids, as shown by their fertilising only the
- ↑ 'Die Befruchtung,' &c. p. 235.
- ↑ Treviranus confirms ('Bot. Zeitung,' 1863, p. 10) a statement made by Salisbury, that when the filaments in the flowers of another leguminous plant, Edwardsia, fall off, or when they are cautiously separated, a large quantity sweet fluid flows from the points of separation; and as beforehand there was no trace of any such fluid, it must have been contained, as Treviranus remarks, within the cellular tissue. I may add an apparently similar, but really distinct case, namely, the presence of nectar in several monocotyledonous plants (as described by Ad. Brongniart in 'Bull. Soc. Bot. de France,' tom. i. 1854, p. 75) between the two walls (feuillets) which form the divisions of the ovarium. But the nectar in this case is conducted to the outside by a channel; and the secreting surface is homologically an exterior surface.
- ↑ 'Die Befruchtung,' &c. p. 84.
- ↑ 'Ult. Osservazioni sulla Dicogamia,' 1875, p. 121'.
