observed the common wasp (Vespa sylvestris) sucking the nectar out of the open cup-shaped labellum. I thus saw the act of fertilisation effected by the pollen-masses being removed by the wasps, and afterwards carried attached to their foreheads to other flowers. Mr. Oxenden also informs me that a large bed of E. purpurata (which is considered by some botanists to be a distinct species, and by others a variety) was frequented by "swarms of wasps." It is very remarkable that the sweet nectar of this Epipactis should not be attractive to any kind of bee. If wasps were to become extinct in any district, so probably would the Epipactis latifolia.
To show how effectually the flowers are fertilised, I may add that during the wet and cold season of 1860 a friend in Sussex examined five spikes bearing eighty-five expanded flowers; of these, fifty-three had the pollinia removed, and thirty-two had them in place: but as many of the latter were immediately beneath the buds, a larger number would almost certainly have been afterwards remowed. In Devonshire I found a spike with nine open flowers, and the pollinia in all were removed with one exception, and in this case a fly, too small to remove the pollinia, had become glued to the rostellum, and had there miserably perished.
Dr. H. Müller has published[1] some interesting observations on the difference in structure and manner of fertilisation, as well as on the intermediate forms between Epipactis rubiginosa, microphylla, and viridiflora. The latter species is remarkable for the absence of a rostellum, and for being regularly self-fertilised. Self-fertilisation here follows from the incoherent pollen-grains in the lower part of the pollen-masses
- ↑ 'Verhandl. d. Nat. Ver. f. Westfal.' Jahrg. xxv. III. Folge, v. Bd. pp. 7–36.
