Juglans sigillata, known as the Iron Walnut, is a species of walnut tree. The tree has been cultivated for its edible nuts. The nuts are oval-shaped with bumps and ridges. The tree is also use for its wood. It is commonly found in Yunnan, but are also found in Guizhou, Sichuan and Xizang in China. It is sometimes grown in gardens and parks as an ornamental plant.