potamogeton

Century Dictionary and Cyclopedia

1. n. A genus of freshwater plants known as pondweeds. the type of tribe Potameæ in the order Naiadaceæ. It is distinguished from the allied genus Ruppia by the sessile nutlets and also by the presence of a calyx; and is further characterized by its numerical plan in fours, each flower having four roundish sepals. four stamens, four styles, and four distinct ovaries producing four small rounded drupes or nutlets, each with a thick, rigid, or spongy pericarp, and a single seed containing an annular or spirally coiled embryo. There are over 50 species, scattered throughout the world, growing in still rivers, ponds, and lakes, with one or two in brackish waters. (See pondweed.) A few species have acquired other names in local use. as, in England, P. densus, the frog's lettuce or water-caltrops, and P. natans, the tench-weed or deil's-spoons, and in America P. amplifolius, the cornstalk-weed. (See heterophyllous, 1.) A large number of aquatic plants, supposed to belong to the genus Potamogeton, have been described under that name by paleobotanists; they come from various regions, and from several divisions of the Tertiary.

WordNet 3.0

1. n. a large genus of aquatic herbs found in quiet waters in temperate regions; leaves usually float on the water