Geitonogamy

Geitonogamy is a form of pollination in flowering plants in which pollen from a flower fertilizes a different flower on the same individual plant. This contrasts with autogamy, where self-pollination occurs within a single flower, and xenogamy, where pollen comes from a different individual plant.

Geitonogamy is typically mediated by pollinators that move between flowers on the same plant, though wind or mechanical transfer can also accomplish it. It is common in many plant groups, including perennials and clonal species where many flowers originate from a single genet. Because the donor and recipient flowers are on the same plant, geitonogamy often yields a high degree of relatedness among offspring and can contribute to selfing or inbreeding, depending on whether between-flower mating bypasses any pollen-pistil incompatibilities.

The genetic and evolutionary consequences of geitonogamy depend on the plant’s mating system. Some species possess self-incompatibility mechanisms or other barriers that reduce selfing, including geitonogamy, whereas others show mixed mating systems with substantial geitonogamous reproduction under certain ecological conditions. Geitonogamy can thus influence reproductive assurance when opportunities for crossing between genets are limited, and it can interact with pollinator behavior, floral display, and plant architecture to shape genetic structure within populations.

In plant reproductive biology, geitonogamy is distinguished from autogamy and xenogamy and is a key component in studies of pollen flow, mating-system evolution, and progeny genetics.