Sectioned primrose flowers (Primula vulgaris) Science Image

Ref: 500082



Sectioned primrose flowers (Primula vulgaris) showing the differing positions of the stamens that can be found in these flowers. The pin-eyed flower (left) exhibits a long style which reaches to the top of the corolla tube and stamens which are half-way down the tube. The thrum-eyed flower (right) has its stamens at the top of the corolla tube with its style reaching only half-way up the tube. This arrangement which results in cross-pollination from visiting insects, is known as heterostyly because the flowers exist in two forms with styles of differing lengths.