Mode of Pollination - water pollination in Vallisneria :
The plant is dioecious.On maturity, the male flowers get detached from the parent plant and float up and come to the surface of water.At the same time, the female flowers also rises up to the surface of water by straightening of the coiled stalk. The detached male flowers cluster around the floating female flower and dehisce, thereby performing pollination. The long stalks of the female flower begin to coil down to the bud lelvel where the fruit ripens.