Water caltrop, Buffalo nut, Water chestnut, Devil pod, Spiny pod, Exotic flower seeds (lat. Trapa manshurica, Trapa natans).
An annual aquatic plant, a species of the genus Rogulnik of the family Derbennikovye (Lythraceae). The stem of the chilim is under water, develops in the spring from the fruit and reaches the surface of the water. It is 3.6-5 m in length. The roots are greenish, pinnately branched, located on a stem submerged in water and have the appearance of underwater leaves.
The plant has two types of leaves: the first type is underwater - opposite, linear, located along the stem above the roots, located in the water column; the second is floating on the surface. Floating leaves are located at the end of the stem, form a rosette.
The flowers are white, located in the axils of the leaves, pollinated by insects. The flower has four sepals, petals and stamens. There is one pistil, blooms in May - June.
The fruit is a black-brown nut 2-2.5 cm across, with two to four sharp horns. The fruits ripen in August - September. Chilim fruits can be used for food. Under the hard shell is a white edible kernel. It represents a nutritious and delicious product.
The plant reproduces by fruits separating from the stem and spreading to other places by the current.
Prefers muddy soils of slow-flowing or stagnant reservoirs. Often forms solid thickets. It is sensitive to the composition of water, light and temperature.