Hippuris vulgaris (from Greek: ἵππος — horse and οὐρά — tail), known as mare's-tail or common mare's-tail, is a common aquatic plant of Eurasia and North America ranging from Greenland to the Tibetan Plateau to Arizona. It prefers non-acidic waters.
The common mare's tail is a creeping, perennial herb, found in shallow waters and mud flats. It roots underwater, but most of its leaves are above the water surface. The leaves occur in whorls of 6-12; those above water are 0.5 to 2.5 cm long and up to ...