Pollen baskets on a mining bee (Halictus sp.). As the bee sucks nectar from the flower, its sacks rub against the stamens, inadvertently 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. This bee is so named because the female burrows into the ground to build a nest, digging chambers for her eggs and lining them with a waxy secretion.