Qian Shi

Euryale ferox Salisb. (Nymphaeaceae) is a robust aquatic perennial herb of warm freshwater ponds and lakes, with a stout rhizomatous rootstock anchored in the mud and all aerial parts heavily armed with sharp spines. The leaves are floating, peltate to almost orbicular and very large, often 0.6 to 1.3 meters across in mature plants, with a quilted, deeply puckered upper surface that is dark green and a purplish, prominently veined and spiny lower surface. The flowers are solitary on short, stout, spiny peduncles, partly submerged or just at the water surface, 3 to 5 cm across, with many narrow violet-purple petals enclosed by four large, spiny sepals. The fruit is a globose, spongy, spiny berry 5 to 10 cm in diameter containing many roughly spherical, pea-sized seeds with a brittle, dark shell and a starchy white kernel. The hulled, dried kernels, Qian Shi, are harvested in late summer to autumn and are used in Chinese medicine.