Marestall

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 3 mm wide, whereas those under water are thinner and limper, and longer than those above water, especially in deeper streams. The stems are solid and unbranched but often curve, and can be up to 60 cm long. In shallow water they project 20–30 cm out of the water. It grows from stout rhizomes. The flowers are inconspicuous, and not all plants produce them.