Field and Woodland Plants

the latter case it cannot be obtained by insects unless they bore into the substance of the spur, and the delay caused renders the removal of the pollen more certain. While the nectar is being withdrawn, the head of the insect is pressed against a sticky disc at the base of the pollen masses, with the result that both disc and pollen masses are bodily removed, and the insect leaves the flower with the whole attached to its head.