Poppy flower. Close-up of the reproductive structures of a poppy flower (Papaver sp.). The pollen grains (brown), which contain the male sex cells, are produced on the anthers (black). These surround the fused stigmas (green) at the top of the female reproductive structure (carpel), also composed of the style and the ovary (neither seen). Pollen grains land on the stigma, allowing the male sex cells to move down the style into the ovary, where they may fertilise the female sex cells (ovules). The carpel may then ripen into a capsule containing seeds.