Hydrophily is a specialized and relatively uncommon form of pollination in which pollen is distributed by water, especially in aquatic environments like rivers, streams, or submerged habitats. It occurs mainly in certain aquatic plants whose reproductive parts are adapted to water-based pollen transfer
. There are two main types of hydrophily:
- Surface hydrophily (epihydrophily): Pollen is released onto the water surface and carried by currents to the female flowers, which often have parts reaching the water surface. For example, in Vallisneria , male flowers detach and float on the water surface to reach female flowers
- Submerged hydrophily (hypohydrophily): Pollen is released and transported beneath the water surface, directly reaching submerged female flowers. This occurs in plants like Najas and seagrasses such as Zostera marina
Hydrophilous flowers typically have small, inconspicuous blooms without bright colors, scent, or nectar, as they do not rely on animal pollinators. Their pollen grains are adapted to resist water and may have special shapes or coverings to survive underwater transport. Female flower stigmas are often elongated or specially adapted to capture water-borne pollen effectively
. Hydrophily is unique to fully submerged aquatic angiosperms and represents an evolutionary adaptation to aquatic life, facilitating sexual reproduction in water environments where wind or insect pollination is ineffective
. Examples of hydrophilous plants include Vallisneria , Hydrilla , Zostera , and Najas
. In summary, hydrophily is pollination by water, involving the transfer of pollen through water currents either on the surface or submerged, adapted to aquatic plants' reproductive needs.
