Anther
The tip of a stamen, where pollen is made and released.
Also: pollen sac
The anther is a small sac, or pair of sacs, at the top of a stamen. When it is ripe it splits open and the pollen inside is exposed, ready to be carried off by an insect, a bird or the wind. On a lily the anthers are large and rust-coloured, and they swing loosely on their stalks. On a tulip they are dark and stand upright around the centre. The colour of fresh anthers is one sign florists use to judge how recently a flower opened.