Ku Shen

Sophora flavescens (Ku Shen, shrubby sophora) is a perennial subshrub or herbaceous perennial in the Fabaceae family, growing 50 to 150 centimeters tall from a long, cylindrical, yellowish woody taproot that constitutes the medicinal material. The erect, ridged, sparsely branched stems bear alternate, odd-pinnate leaves 20 to 25 centimeters long with 11 to 25 ovate to oblong-lanceolate leaflets 3 to 4 centimeters long, finely pubescent on the lower surface. From mid summer to early autumn, dense terminal racemes 15 to 25 centimeters long bear numerous pale yellow to cream papilionaceous flowers about 1.5 centimeters long, characteristic of the legume family. The legume pods are linear-cylindrical, 5 to 10 centimeters long, slightly constricted between the seeds, with a long beak. The bark of the root is yellowish-brown, the wood pale yellow and intensely bitter when chewed, giving rise to the Chinese name Ku Shen (bitter root). Native to East Asia, widely distributed across China, Korea, Japan, and Russia.