Split wood, alias split wood, is the inner diaphragm of walnut. Alias walnut coat, nutcracker, walnut partition, walnut core, Latin name Juglansregia. Deciduous tree, fruit is nearly spherical, drupe-shaped, and the exocarp is green. It tastes bitter, flat and non-toxic. Distributed in Hebei, Henan, Shanxi, Shandong, Yunnan and other places in China. It is not recommended to use the branch wood of native walnut as medicine, and the grafted walnut is not recommended because of its branch wood degradation and scions introduced from other places.