Page:Darwin - The various contrivances by which orchids are fertilized by insects (1877).djvu/113

. IV.

NEOTTEÆ.

have now arrived at a third tribe, the Neotteæ of Lindley, which includes several British genera. These present many interesting points with respect to their structure and manner of fertilisation.

The Neotteæ have a free anther standing behind the stigma. Their pollen-grains are tied together by fine elastic threads, which partially cohere and project at the upper end of the pollen-mass, being there attached (with some exceptions) to the back of the rostellum. Consequently the pollen-masses have no true and distinct caudicles. In one genus alone (Goodyera) the pollen-grains are collected into packets as in Orchis. Epipactis and Goodyera agree pretty closely in their manner of fertilisation with the Neotteæ, but are more simply organised. Spiranthes comes under the same category, but has been differently modified in some respects.

Epipactis palustris. —The lower part of the large