water-chestnut	USDA PLANTS Symbol: TRNA USDA ARS GRIN: 36824 ITIS: 27170 NAPIS: PCGABBA
Trapa natans L.
Taxonomic Rank: Magnoliopsida: Myrtales: Trapaceae
States Listed: Idaho, Oregon, Washington,
Synonym(s): water chestnut, water nut
Water chestnut is a rooted, floating plant that invades shallow to deep, fresh water habitats in the northeastern United States. Water chestnut can grow in 12 to 15 ft. (3.6-4.6 m) of water and forms dense, floating mats, often three layers deep. Leaves on the surface of the water are alternate, triangular in shape, strongly toothed and connected to the stem by an inflated petiole. Submerged leaves are feathery and either opposite or alternate. Flowering occurs from mid-summer to frost. Small, four-petaled flowers give way to the nut-like fruit. The fruit have two to four, ½ in. (1.3 cm) long, sharp, barbed spines. The spines can penetrate shoes. The dense, floating mats restrict light availability, reduce the oxygen content, and displace other emergent and floating vegetation. Water chestnut also limits boating, fishing, swimming and other recreational activities. Water chestnut is native to Europe and Asia and was first observed in the United States in Massachusetts in the late 1800s.

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Identification, Biology, Control and Management Resources

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