POTAMOGETON, POND-WEED: A genus of the tetragynia order, belonging to the tetradria class of plants; and in the natural method ranking under the 15th order, Inundate. There is no calyx; but four petals; no style, and four seeds. There are 12 species, all of them floating vegetables on the surfaces of stagnant waters, affording an agreeable shade to fish, and food to cattle.