Water Chestnut
Trapa natans

Origin: Europe, Asia and Africa

Background
Water chestnut was first observed in North America near Concord, Massachusetts in 1859. The exact path for the introduction is unknown.

Description
An annual aquatic plant with a submerged stem; stems can reach 12 to 15 feet in length; very fine roots anchor the plant into the mud. Leaves at the water's surface, the plant contains a rosette of floating leaves. The saw-tooth edged leaves are triangular in shape and connect to an inflated petiole, which provides added buoyancy for the leafy portion; additional, feather-like leaves can be found along the submerged stem. Four-petaled white flowers form in June and are insect-pollinated. The fruit is a nut with four 1/2-inch, barbed spines. Seeds can remain viable for up to 12 years, although most will germinate within the first two years.