Stem: The unbranched stem is hollow, up to 1 m long, and forms roots at the nodes. The stem is erect when emergent; limp when submersed; and can form creeping rhizomes.

Flower: Small, inconspicuous flowers are located at the leaf bases. The flowers which lack petals and sepals, are reduced to a tiny rim.

Fruit: Tiny (mature fruit about 2 mm long), nut-like, located at leaf bases.

Root: Fibrous. Arising from lower portion of stems and rhizomes.

Propagation: Seeds, rhizomes. Will regrow from stem cuttings.

Importance of plant: Seeds and sometimes vegetation eaten by waterfowl and shorebirds. Provides shelter for small animals. Sometimes used in ornamental ponds or cool-water aquariums.

Distribution: Occurs in cooler regions of North and South America, Eurasia, and Australia. It is one of the few aquatic plants found in arctic pools and lakes.

Habitat: At the edges of lakes, ponds, and streams in fresh, usually shallow water, though it will grow in water up to 2 m deep.

May be confused with:  Horsetails (Equisetum) and parrotfeather (Myriophyllum aquaticum). Horsetails have corrugated, distinctly jointed stems. Parrotfeather has divided feather-like leaves rather than simple, narrow leaves. Submersed mare’s-tail plants may be confused with members of the oxygen plant family (Hydrocharitaceae), but mare’s-tail has more leaves per whorl. A closely related plant, mountain mare’s-tail (H. montana) is found in high elevation wet meadows or on mossy banks. It is more terrestrial, smaller (to 10 cm), and has shorter leaves (to 10 mm long) than common mare’s-tail.

Photographs: Hippuris vulgaris

Line Drawings: None available