herkogamy

Herkogamy is a floral trait in which the spatial arrangement of a flower’s reproductive organs—the stamens (anthers) and the pistil (stigma and ovary)—creates a physical separation between male and female parts. This separation lowers the chance of self-pollination and tends to promote cross-pollination through pollinator-mediated pollen transfer.

There are two principal configurations of herkogamy. In approach herkogamy, the stigma is positioned above the level of the anthers. In reverse herkogamy, the arrangement is the opposite, with the anthers above the stigma. These different orientations influence how pollinators contact the reproductive organs as they visit the flower and can affect the likelihood of pollen on the same flower and subsequent self-fertilization.

Herkogamy often occurs alongside other floral strategies that influence mating systems. It can reduce self-pollen deposition and work in concert with dichogamy, the temporal separation of male and female phases. In some taxa, herkogamy is part of a broader heterostylous system, where reciprocal placement of anthers and stigmas between floral morphs enhances cross-pollination between morphs.

Measurement and study of herkogamy typically involve quantifying the vertical distance between the stigma and the anthers within flowers and comparing this trait across individuals, species, or environmental conditions. The presence and form of herkogamy can vary widely among angiosperms and is influenced by pollinator behavior and evolutionary history.

See also: dichogamy, heterostyly, self-incompatibility.