The water chestnut is an annual aquatic plant not native to the United States, categorized as an invasive species in the Connecticut River Watershed. The water chestnut is a rooted, floating aquatic plant. It has rosettes of leaves that float on the surface of the water that appear to be radiating from a central point. They are triangular or slightly diamond shaped, toothed on two sides and connected to the stem by a long, flexible submerged stalk. Submerged leaves are feathery and either opposite or alternate. Very small, white four-petaled flowers bloom in July. The seeds are four-horned nut-like structures that mostly develop on the underside of the floating rosette. Seeds ripen in about a month (ripe seeds start to drop around the end of July or early-mid August).These seeds remain viable for up to twelve years. One seed can produce up to 15 rosettes, producing up to 20 more seeds, and quickly covering the water surface.