In Vallisneria pollination is through hdrophilly ie through water. In Valilisneria, the female flower appear on the surface of the water as it have a long stalk. The pollen grains released by the male flower reaches to female flower for fertilisation through water currents.
A mixed mode of submarine and surface hydrophilous pollination occurs in the seagrass Zostera marina L. In the surface mode of pollination, pollen rafts or ‘search vehicles’ which superficially resemble snowflakes, form at low tide and are transported on the surface of the sea by winds and water currents.