Red Water Chestnut of Taihu Lake

Red Water Chestnut of Taihu Lake

　　Water chestnut is an annual floating-leaved aquatic plant of the Trapaceae family, with quite distinctive stems, leaves, and fruits. Its main root is relatively weak, extending several feet into the mud at the bottom of the water to anchor the plant and absorb nutrients. The slender stem lies entirely submerged, with branches and “root-like tendrils” that also aid in absorption. There are two types of leaves, clustered on a shortened stem — the ones that float on the water’s surface are called floating leaves. They are inversely triangular in shape and interlock to form a disc-like structure commonly known as a water chestnut “plate.” Each plate consists of 40–60 leaves. The leafstalks are thick and fleshy, with a swollen middle section that forms an air sac, enabling the leaves to float. The submerged leaves are long and narrow, thread-like, without distinct petioles or blades. In late summer to early autumn, small flowers bloom in the leaf axils — they are white or reddish-white. After pollination, the flowers bend downward and submerge into the water, eventually developing into the fruit known as the “water chestnut.” The seed coat hardens into the characteristic sharp horns of the fruit. Depending on the presence and number of these horns, they are categorized as hornless, three-cornered, or four-cornered water chestnuts. The young fruits come in green, red, or purple hues, while the mature ones develop a hard black shell with milky-white flesh inside. The edible part is the thick cotyledon of the seed.