The anther is a part of the stamen, which is the male reproductive part of a flower. It is located at the top of the stamen and produces and contains pollen grains. The anther is usually borne at the tip of a long, slender stalk known as a filament. It consists of two lobes that each house a pair of pollen sacs (microsporangia) that produce pollen for pollination. As the anther matures, the partition between the adjacent microsporangia of a pair breaks down so that there are only two pollen-containing sacs (one in each lobe of the anther) at the time the anther releases the pollen. While the anthers of most angiosperms dehisce, or release, pollen through a rupture along one side of each sac, those belonging to members of the heath family (Ericaceae) characteristically release pollen through small pores at the anther tip.