Fig. 467.
Cypripedium.
Fig. 468.
Section of flower of cypripedium. st, stigma; a, at the left stamen. The insect enters the labellum at the center, passes under and against the stigma, and out through the opening b, where it rubs against the pollen. In passing through another flower this pollen is rubbed off on the stigma.
862. If we open carefully canna flower buds which are nearly ready to open naturally, by unwrapping the folded petals and staminodia, we shall see the anther-bearing staminodium is so wrapped around the flattened style that the anther lies closely pressed against the face of the style, near the margin opposite that on which the stigma lies.
Fig. 469.
Epipactis with portion of perianth removed to show details. l, labellum; st, stigma; r, rostellum; p, pollinium. When the insect approaches the flower its head strikes the disk of the pollinium and pulls the pollinium out. At this time the pollinium stands up out of the way of the stigma. By the time the insect moves to another flower the pollinia have moved downward so that they are in position to strike the stigma and leave the pollen. At the right is the head of a bee, with two pollinia (a) attached.