Honey bee (Apis mellifera) pollinating a honey wort flower (Cerinthe sp.). As the bee sucks nectar from the flower, it rubs against the stamen - picking up grains of pollen. Each pollen grain contains a male gamete which, when deposited on another plant of the same species, can fertilise an ovule and produce seeds. A large pollen basket, filled with grains of pollen, is visible on the bee's rear.