WATER CALTROP

Trapa spp.

Description Forms dense mats, blocking waterways. Its leaves can float or grow under the water, and it produces nuts with sharp spines.

Leaves Submerged leaves are feather-like and arranged in whorls around the stem.

Surface leaves are glossy on top, have fine hairs underneath, 2–3 cm long, on stalks with a round bulge. They are oval, triangle or diamond-shaped with toothed edges.

Flowers White with four petals, 8 mm long.

Fruit Hard and woody with sharp spines, 3 cm wide.

Stems Submerged, 3.6–4.5 m long.

Roots Very fine, 8 cm long and anchored into the mud.

Dispersal Seed or vegetative reproduction from plant fragments dispersed by waterways, attached to birds, animals, vehicles, watercraft and fishing equipment. Usually introduced through intentional planting by humans.

Confused with Introduced species Mosaic flower (Ludwigia sedioides)

Control Please do not attempt to treat or dispose of this weed yourself. Call (02) 6623 3800 if you see this plant anywhere in the Far North Coast region.