Lady's slipper orchids are orchids in the subfamily Cypripedioideae, which includes the genera Cypripedium, Mexipedium, Paphiopedilum, Phragmipedium and Selenipedium.They are characterised by the slipper-shaped pouches of the flowers – the pouch traps insects so they are forced to climb up past the staminode, behind which they collect or deposit pollinia, thus fertilizing the flower. Unlike other orchids, Cypripedioideae have two fertile anthers they are "diandrous".
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