Lily flower stamens. Macrophotograph of the male reproductive part (stamen) of a yellow day lily (Hemerocallis lilioasphodelus) flower. Each stamen is made up of a supporting filament and a pollen sac (anther, brown). The anthers have ripened and split open (dehisced) to reveal pollen (yellow grains). Pollen is the plant's male sex cell that is carried from flower to flower by pollinating insects, which feed on the flower's nectar.