Resupination, rings a bell? In orchids, the lip (labellum) is always at the top of the flower when in bud. But before the flower opens, it turns 180 degrees in most orchids so that the lip comes at the bottom. Thus, the lip forms a landing strip for pollinating insects.
Not all orchids resupinate their flowers, it depends on their pollinator. Species with a hanging inflorescence may even resupinate 360 degrees to get the lip downwards.

Gab van Winkel
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