Wild Yam P.E.
The dried tuber of the perennial creeping herb of the diosciaceae family Diostenta oppositae thunb. Winding grassy vine, tubers long cylindrical, vertical growth, up to 1 m long, white in section when fresh, sticky, white powder after drying. The stems are usually purplish-red, right-handed, and glabrous. It grows on hillsides, valley forests, streams, roadside shrubs or weeds; Or for cultivation. It is distributed in North China, East China, Central South and Northwest China. After the stalks and leaves are withered, they are dug, the roots are cut off, washed, the outer skin and whisker roots are removed, smoked with sulfur, and dried; There is also a choice of hypertrophied and straight dried yam, put in clean water, soaked until there is no dry heart, stuffy, smoked with sulfur, cut the ends together, rubbed into a cylindrical shape with a wooden board, dried in the sun, lighted, commonly known as "light yam".