Water Caltrop (Trapa natans)

Water Caltrop seedThe water Caltrop (also known as Water Chestnut, Buffalo Nut, Bat Nut, Devil Pod, and Singhara) is an aquatic plant that roots in the mud and has finely divided leaves that grow underwater. The Waster Chestnut stem grows 12-15 feet in length and is anchored to the mud via tiny roots.  It has feather-like submerged leaves that grow off the underwater stem.  Its floating leaves are much larger and have saw-tooth edges and are egg-shaped or triangular attached to inflated stems (which provide additional byouancy).  Its white flowers have four petals.  The fruits, borne underwater, have four barbed spines on them.

Where to Find: Water Caltrop plant floating on waterThe water chestnut is a freshwater plant only. It is a native of Asia but has spread to many parts of the world in both temperate and tropical areas.  It prefers sandy, loamy, and clay soils near slow moving water up to a few feet deep, with lots of sun.

Edible Parts: The fruits are edible raw and cooked. The seeds are also a source of food but should be cooked to remove any toxins.

Note: This species should not be confused with the unrelated Eleocharis dulcis, also known as “water chestnut” and familiar to westerners where it is common in Western-style Chinese food.

Cultivated Water Caltrop on farm

Water Caltrop growing in the wild

Water Caltrop leaves

The barbed water chestnut

Flower on water chestnut plant

Barbed Water Caltrop seed

Color drawing of Water Caltrop illustrating the various plant components