Geranium flower stigma. Coloured scanning electron micrograph (SEM) of the stigma of a geranium flower (Geranium thunbergii). It is covered in tiny projections known as papillae (green/brown), which trap grains of pollen. The stigma is part of the female reproductive structure (pistil), which is formed from one or more carpels. Each carpel consists of a stigma, a style and an ovary (not seen). If the female sex cells (ovules) in the ovary become fertilised by the male genetic material which pollen grains contain, the carpel may ripen to produce a fruit containing seeds. Magnification: x120 at 6x7cm size.