Mountain Bean Root (Latin name: Euchresta japonica), also known as Three-leaved Mountain Bean Root and Hu Dou Lian, is a plant of the legume family, genus Euchresta. It is a vine-like shrub that does not branch much and often has adventitious roots on its stem. The leaves consist of only three leaflets, with a leaf stalk that is 4-5.5 centimeters long and has short soft hairs. The leaflets are thick and papery, and elliptical in shape. It grows in dense forests in valleys or on mountain slopes at an altitude of 800-1350 meters. It is found in Guangxi, Guangdong, Sichuan, Hunan, Jiangxi, and Zhejiang provinces in China, as well as in Japan.
Source The main source of Mountain Bean Root is the root of the legume plant Guang Dou Gen (Euchresta formosana). It is harvested in April to May or August to September, and the stems, leaves, and adventitious roots are removed before being washed and dried.
Morphology Guang Dou Gen, also known as Refined Branch Sophora, is a shrub that grows upright or almost horizontally, reaching a height of 1-2 meters. It usually has 2-5 cylindrical, yellow-brown roots. The stem is cylindrical with grooves on the surface and is densely covered in short soft hairs. The upper part of the stem often bends in a zigzag shape. The compound leaves are odd-pinnate and alternate, with 11-17 leaflets. The leaflets are clustered, ovate or elliptical in shape, 1-2.5 centimeters long and 0.5-1.5 centimeters wide. The largest leaflet is usually elliptical in shape, with a smooth margin, dark green on the upper surface and covered in short hairs, and gray-brown on the lower surface, densely covered in gray-brown short soft hairs. The leaflet stalks are short and covered in short soft hairs. The inflorescence is terminal and raceme-like, 12-15 centimeters long and covered in short hairs. The calyx is broadly bell-shaped, sparsely hairy on the outside, with 5 triangular short teeth at the apex. The corolla is yellowish-white in color and butterfly-shaped. There are 10 stamens, with the anthers on the back and slender filaments. There is 1 pistil, with the superior ovary being cylindrical and the style being curved, with a rounded stigma and densely covered in long soft hairs. The fruit is dark purple and bead-like. The flowering period is in April to May.
Habitat It grows at the foot of rocky mountains or in crevices. It is mainly distributed in the southern part of China, with Guangxi being the main producer.
Properties The dried root of Mountain Bean Root is irregularly nodular, with the top often retaining stem bases or stem scars, and several roots growing below it. The root is elongated cylindrical, sometimes branched, slightly curved, 10-36 centimeters long and 0.3-1 centimeter in diameter. The surface is brown to dark brown, with longitudinal wrinkles and slightly protruding lenticels. It is hard and difficult to break, with a slightly flat and light brown cross-section, and visible annular growth rings, but no pith in the center. It has a weak odor and an extremely bitter taste. The larger and more powdery the root, the better.
Processing Remove impurities, classify by size, soak in water, remove and slice after being thoroughly moistened, and then dry.
