Bai (Ci) Ji Li

Tribulus terrestris is a prostrate, mat-forming annual herb of the Zygophyllaceae, widespread across temperate and tropical regions of the Old World and naturalised elsewhere. The hairy, branching stems radiate from a slender taproot, bearing opposite, pinnately compound leaves with 5–8 pairs of small oblong leaflets. Solitary yellow, five-petalled flowers about 8–12 mm across arise in the leaf axils through summer. The distinctive fruit is a hard schizocarp that splits at maturity into five woody, wedge-shaped mericarps, each armed with two stout divergent spines — the source of the common names 'puncture vine' and 'goat's-head'. The plant favors dry, sandy, disturbed ground. The dried mature fruit is the medicinal organ in both Chinese and Ayurvedic pharmacopoeias.