Pea flower stigma. Coloured scanning electron micrograph (SEM) of the surface of a common or garden pea flower (Pisum sativum) stigma. This is part of the female reproductive structure (pistil), which is formed from one or more carpels. Each carpel possesses a stigma, with a style and an ovary (not seen). The stigma is covered in projections known as papillae (green). These trap pollen grains (yellow) that contain the male sex cells. If the male cells fertilise the female sex cells (ovules) in the ovary, the carpel may ripen to produce a fruit containing seeds. Magnification: x140 at 6x7cm size.