How is pollination carried out in water plants?

Pollination carried in water plants are in following ways:

i. Pollination above the surface of water: In few species, female flower reach the surface of water by the long stalk and pollen grains from male flowers are released on to the surface of water. These pollen grains are carried by water currents. And out of these some of them reach the female flowers and the stigma. For example in Vallisneria

ii. Pollination below the surface of water: In few species, female flowers remain submerged in water and the pollen grains are released inside the water. Pollen grains in such species are long, ribbon like and they are carried passively inside the water; some of them reach the stigma and achieve pollination. Example Seagrasses.