The condition of flowering plants in which flowers of the same species have styles of different lengths, so that the stigma is positioned below the anthers in some flowers and above them in others. This ensures that pollinating insects are more likely to transfer pollen from the anther of one flower to the stigma of another, thus promoting cross-pollination. Species showing heterostyly include the primrose (see illustration).

Heterostyly in the primrose (Primula vulgaris)