This is the fruit of the piercing dragon or yam, the piercing dragon, alias piercing dragon dioscorea, wild yam, skewer of the ground dragon, ground dragon bone, chicken bone, dragon castor seed. Perennial twining herbaceous vines, rhizomes walk horizontally, corky skin is flaky off, yellow in cross section. Stem left glabrous. Leaves alternate palmately cordate, variable, entire. Flowers unisexual, spikes axillary; male flowers sessile, perianth 6-lobed, stamens 6; female flowers often solitary, perianth 6-lobed. Capsule obovate-ellipsoid, with 3 broad wings. Seeds 2 per locule, borne at the base of each locule, surrounded by unequal broad membranous wings. Flowering period June to August, fruiting period August to October. Born on mountain slopes near forests, under shrubs, and along ditches, mainly in Liaoning, Jilin, Heilongjiang, Hebei, Nei Mongol, Shanxi, and Shaanxi. As medicine for its rhizome, it has the effect of relaxing tendons and activating collaterals, dispelling wind and relieving pain.