Alias river white grass, snake retreat, pear head thorn and snake. Plant name, mother of charcoal. Derived from the aerial parts of Polygonaceae plant Polygonum perfoliatum.

Plant morphology perennial Polygonum herb. The stems are angular, reddish brown and have inverted barbs. Leaves alternate and peltate; Leaf blade is nearly triangular, 4 ~ 6 cm long and 5 ~ 8 cm wide, with sharp apex, nearly heart-shaped or truncated base, and sparse barbs along the lower vein; Stipules sheath nearly round, supporting stem; Petiole long, sparsely spiny. Inflorescence short spike; Bracts rounded; Perianth 5-parted, reddish or white, enlarged when bearing fruit, fleshy and dark blue; Stamens 8; Style 3-lobed. Achenes are spherical and wrapped in blue juicy perianth. The flowering period is June-August, and the fruiting period is 9-65438+1October.

Born in valleys, bushes or ditches. Location: Jiangsu, Zhejiang, Fujian, Jiangxi, Guangdong, Guangxi, Sichuan, Hunan and Guizhou.

Picking, cutting and drying when flowers bloom in summer.

Chemical constituents include glycoside, horseradish peroxidase, p-coumaric acid, ferulic acid, vanillic acid, protocatechuic acid and caffeic acid.

It tastes slightly cold and sour.

Function: diuretic, detumescence, clearing away heat and toxic materials and relieving cough. Used for nephritis edema, whooping cough, diarrhea, eczema, furuncle and snake bite.