Lythraceae

Trapa natans

Common Names: Water caltrop

Plant Form: Mat forming aquatic herb. Size: Can reach 4.5 m deep. Stem: Submerged. Leaves: Submerged leaves feather like in whorls around stem. Surface leaves 2-3 cm long in rosette in oval, triangle or rectangle shape with saw-toothed edges. Flowers: White with 4 petals, above surface. Fruit and Seeds: Hard, woody or bony nut, 3 cm wide with sharp spines. Habitat: Dams, ponds and lakes. Distinguishing Features: Easy to distinguish. Impacts: Eliminates native plants, reduces available oxygen in water, clogs irrigation, sharp spikes can harm people and animals.

Leaves

Floats on leaf stems

Floating foliage forms a pattern

Seeds are large, woody and pointed