1 Zhao Shi, famous. It is a mature seed kernel of Euryale ferox in Nymphaeaceae. It is an annual aquatic plant that grows in lakes and ponds. Zhao Shu's stems and leaves have thorns and purple flowers, and fruits have hard shells and thorns. Location: Hunan, Jiangxi, Anhui, Shandong and other places. Harvest ripe fruits in late autumn and early winter, peel, take out seed kernels, remove hard shells and dry them in the sun. Raw, mashed or fried.