Page:On the Various Contrivances by Which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.djvu/30

brush that, whilst brushing upwards against the rostellum, I pushed against the blunt solid end of the anther (see Sect. C ); this at once eased the pollinia, and they were withdrawn in an entire state. At last! understood the mechanism of the flower.

The large anther stands nearly parallel and behind the stigma (Sect. C), so that the pollinia when withdrawn by an insect would naturally adhere to its body in a position fitted to strike, as soon as it visited another flower, the almost parallel stigmatic surface. Hence we have not here, or in any Neottee, that movement of depression so common with the pollinia of the Ophree. When an insect with the pollinia attached to its back or head enters another flower, the easy depression of the distal portion of the labellure probably plays an important part; for the pollen-masses are extremely friable, and, if struck against the tips of the petals in the act of entering, much of the pollen would be lost; but as it is, an open gangway is offered, and the viscid stigma, with its lower part protuberant, lying in front, is the first object against which the pollen-masses projecting forwards from the insect's back would naturally strike.^[1] I did not count the flowers, but in one lot of spikes sent me by Mr. More a large majority of the pollinia had been naturally and cleanly removed by some unknown insect.

Epipactis latifolia.

This species agrees with the last in all the foregoing specified details, excepting that the rostellum projects considerably further beyond the face of the stigma, and the blunt upper end of the anther projects less. The viscid matter lining the elastic cap of the rostellum takes a longer time in setting dry. The upper petals and sepals are more widely expanded than in E. palustris: the distal portion of the labellum is smaller, and is firmly united to the basal portion (Fig. XIV.); so that it is not flexible and elastic: it apparently serves only as a landing-place for insects. The fertilisation of this species depends simply on an insect striking in an upward and backward direction the highly-protuberant rostellum, which it would be apt to do in retreating after having sucked the copious nectar in the cup of the labellum. Apparently it is not at all necessary that the insect should push back the less protuberant blunt upper end of the anther; at least I found that the pollinia could be easily removed by simply dragging off the cap of the rostellum in an upward and backward direction.

In Germany C. K. Sprengel caught a fly with the pollinia of this species attached to its back. In England the flowers are much visited by insects: 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, ultimately a larger

1. As it is quite possible that I may have overrated the importance of the peculiar structure of the labellum, I asked Mr. A. G. More to remove the distal half of the labellum from some flowers before they had expanded, but I was too late in my application. He was able to try only two flowers, which were situated near the summit of the spike. These flowers formed seed-capsules, which were certainly small; but this may have been owing to their position. Unfortunately also these capsules shed most of their seed in being sent to me; so that I could not ascertain whether the seeds were well formed. Of the few seeds which did remain within these two capsules many were shrivelled and bad.