BugwoodWiki Article

European water chestnut
Trapa natans L.

Overview

Appearance
Trapa natans is a rooted, floating plant that invades shallow to deep, fresh water habitats in the northeastern United States. It can grow in 12-15 ft. (3.6-4.6 m) of water and forms dense, floating mats, often three layers deep.
Foliage
The rosette of leaves on the surface of the water are alternate, triangular in shape, strongly dentate (toothed) and connected to the stem by an inflated petiole. Submerged leaves are feathery and either opposite or alternate.
Flowers
Trapa natans has small, four-petaled flowers that bloom from July to frost.
Fruit
The nut-like fruit has two to four, 0.5 in. (1.3 cm) long, sharp, barbed spines. They ripen in about a month and can remain viable as long as 12 years. Each seed can produce 1-15 rosettes and each rosette can produce as many as 20 seeds. The spines can penetrate shoes.
Ecological Threat
The dense, floating mats of Trapa natans restrict light availability, reduce the oxygen content, and displace other emergent and floating vegetation. It also limits boating, fishing, swimming and other recreational activities. Trapa natans is native to Europe and Asia and was first observed in the United States in Massachusetts in the late 1800s.

Resources

Selected Images


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0002120

European water chestnut
Trapa natans
Feature(s)
Alfred Cofrancesco
2308042
2308042

European water chestnut
Trapa natans
Flower(s)
Leslie J. Mehrhoff
2308043
2308043

European water chestnut
Trapa natans
Plant(s)
Leslie J. Mehrhoff
5274095
5274095

European water chestnut
Trapa natans
Plant(s)
Leslie J. Mehrhoff
5274097
5274097

European water chestnut
Trapa natans
Fruit(s)
Leslie J. Mehrhoff
5274098
5274098

European water chestnut
Trapa natans
Fruit(s)
Leslie J. Mehrhoff
5309016
5309016

European water chestnut
Trapa natans
Plant(s)
USDA PLANTS Database
5309017
5309017

European water chestnut
Trapa natans
Fruit(s)
Steve Hurst

Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

State Regulated List

Invasive Listing Sources

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Rosidae
Order: Myrtales
Family: Trapaceae
Genus: Trapa

Other System Links

Plants: TRNA
Bayer: TRPNA
GRIN: 36824
ITIS: 27170
NPDN Pest: PCGABBA

Synonyms and Other Names

Other Common Names:
water chestnut, water nut

Categories

Category: Aquatic