Macrophotograph of the flower of a hybrid Hippeastrum ("Amaryllis") houseplant. The picture shows both male and female reproductive structures. Above to right, six curving filaments terminate in anthers. The anthers have split open to expose the pollen grains (pale yellow). Below to the left, a single filament called the style terminates in a tripartite female receptive surface, the stigma (three white highlights). When compatible pollen contacts the stigma, it produces a narrow tube that grows through the stigmatic surface, down the style, and delivers the male gametes to the eggs in the ovary within the flower base. This process is called fertilisation, and results in seed formation.