Species commonly cultivated
Hippuris vulgaris L. (Europe, Asia, North America)
occasionally considered weedy in native range due to overgrowth blocking waterways
Perennial, creeping rhizome with erect leafy stems. Leaves equally spaced along stem in whorls of 8-15, sessile, obovate to linear, entire. Flowers sessile or subsessile, axillary, either bisexual, unisexual or sterile; sepals and petals greatly reduced to rim above ovary. Dispersal by seed in ‘nuts’ and stem fragments.
swamps, ponds, and lakes
Three species are known. Hippuris vulgaris is cultivated for ponds and is highly variable geographically.