Yam, alias Ercaowupu Herbal Medicine, Bianmingyuan in Yan Dynasty, White Yam (Northwest, Jiangsu, Anhui), Bison Tail (Sichuan), Hairdressing Top (Yunnan), long yam (Shanxi), Wild Yam (Guangdong) and Vegetable Yam (Henan). Twisted grass vines. Tubers are long cylindrical and grow vertically, and the length can reach1m. When fresh, the cross section is white and sticky, and when dry, it is white and muddy. Stems usually purplish red, right, glabrous. Simple leaves, alternate in the lower part of the stem, opposite above the middle, rarely 3 leaves; Leaves vary greatly, from an oval triangle to a broadly oval halberd, 3-9 cm long and 2-7 cm wide, with the top gradually tapering, deep heart-shaped, wide heart-shaped or halberd-shaped base to a nearly truncated shape, with the edge often 3-cleft to 3-cleft, the middle lobe oval to lanceolate, the side lobe ear-shaped, round and nearly square to oval, and the joint of two lobes and the middle lobe can be connected into different arcs, even if the shape change of the leaf is the same. At seedling stage, leaves are generally broadly ovoid or ovoid, and the base is deeply heart-shaped. There are usually bulbils in the axils of leaves. Dioecious. The male inflorescence is a spike, 2-8 cm long and nearly erect; 2-8 inserted in leaf axils, occasionally arranged in a conical shape; Inflorescence axis is obviously zigzag; Bracts and perianth segments have purple-brown spots; The outer petals of male flowers are broadly ovoid, and the inner petals are ovoid; Stamens 6. The female inflorescence is a spike, and the inflorescence 1-3 is inserted in the leaf axils. The capsule is non-reflexed, oblate or triangular, with a length of 1.2-2.0cm and a width of 1.5-3.0cm, and white powder outside. The seeds are inserted in the middle of the central axis of each locule and surrounded by membranous wings. The flowering period is from June to September, and the fruiting period is July-165438+1October.