Judas tree flower. Coloured scanning electron micrograph (SEM) of the reproductive parts of the flower of the Judas tree, or redbud (Cercis sp.). The male stamens comprise a long filament (beige) bearing a brown anther. The anthers produce the flower's pollen, the male sex cells. The female carpel comprises a long, thick style (yellow) bearing a small stigma (pale, centre left). Pollination occurs when pollen lands on the stigma. It then burrows down through the style to reach the female sex cell (ovum) in the ovary (not seen) at the base of the style.