Bian Xu (Knotgrass) (Stem cylindrical, slightly flattened, nodes enlarged, green-brown-red, fine raised longitudinal lines)

Authentic Bian Xu (Knotgrass) (Nodes enlarged with reddish-brown membranous sheaths, leaves greenish-brown with entire margins, often falling off, flowers born in leaf axils)

Bian Xu (Knotgrass) (Euphorbia hirta, mistaken)

【Naming】

Bian Xu (Knotgrass)

 【Source】

Shen Nong’s Herbal Classic – Lower Grade

 【Common Usage Level】

E

 【Botanical Origin】

The dried aerial part of Polygonum aviculare L. var. vegetum Ledebour of the Polygonaceae family.

 【Characteristics】

The stem is cylindrical, slightly flattened, mostly curved, 10~30㎝ long, 1.5~3㎝ in diameter, surface is brownish-red or grayish-green, nodes are enlarged, with remnants of reddish-brown membranous leaf sheaths, internodes vary in length, texture is hard, easily broken, the fracture surface shows a yellowish-white pith, leaves are greenish-brown, usually falling off. Flowers are born in the leaf axils, red, but mostly withered and gone; odor is faint, taste is cool.

 【Identification】

The best quality is dry, green-blue in color, and free of mud. Those with flowers and seeds are not suitable for medicinal use.

 【Category】

Whole Herb