A section through a flower of Pinguicula caerulea shows the passage from outside to inside. The furry lump on the lower side of the throat evidently is a signal to a bee that it is on its way toward nectar, and tells it which is the lower side of the flower. If a crawled into the flower with the fury lump below, its back would be contacted by the anthers, which dust pollen on its back (an indentation on the upper part of the tube of the flower, on its upper side) or by the flower's stigma, which picks up pollen. Then a long-tongued bee could get nectar from the spur, which is too narrow for a bee's head but not its tongue.
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