The flower is arguably the centrepiece of angiosperm evolution. Its primary function is to secure pollination — the transfer of pollen from the anther (male) to the stigma (female). As plants are sessile organisms, the extraordinary diversity of flowers in large part reflects countless alternative evolutionary solutions to achieve this critical step in the flowering plant life cycle. The majority of flowering plants, some 87% by one estimate, depend on animals for pollination, with most of these paying for the service of pollination via food rewards of nectar or pollen. As in human economic systems, however, some cheating and deception occurs, with the pollination strategy of sexual deception being one such example. The overwhelming majority of the flowering plants are animal pollinated. While most of these species pay for the service of pollination, some plants cheat the system. In this Primer, Rod Peakall discusses a remarkable case of floral mimicry — sexually deceptive plants which secure insect pollination by offering the false promise of sex.