Trees to 25 m tall. Leaves 15-50 cm; petiole 7-12.5 cm, glabrescent; rachis glabrescent; leaflets 9 or 11(-15), entire or obscurely serrulate; lateral leaflets sessile or petiolule ca. 1 mm, blade ovate-lanceolate or elliptic-lanceolate, 6-18 × 3-8 cm, base oblique, apex acuminate; terminal petiolule 2-3 cm. Male spike 13.5-18 cm. Stamens 24-27. Fruiting spike with 1-3 nuts. Nuts ovoid-globose or subglobose, 3.4-6 × 3-5 cm; husk glabrescent, irregularly dehiscent; shell thick, smooth with 2 or more prominent ridges and deep pits and depressions. Fl. Mar-Apr, fr. Sep.

This distinctive relative of Juglans regia is cultivated in Yunnan for its edible nuts and hard wood. The name refer to the many seal-like depressions (sigillatae) in the shell, and the species has subsequently received recognition in China as the "iron walnut."

Forests in valleys and on mountain slopes; 1300-3300 m. Guizhou, Sichuan, SE Xizang, Yunnan [Bhutan, Sikkim]