Ji Li

Tribulus terrestris is a low-growing, mat-forming annual herb in the Zygophyllaceae family, native to warm temperate and tropical regions of the Old World and now widely naturalized. The trailing stems radiate from a central taproot and reach 10-60 cm long, bearing opposite, pinnately compound leaves with 5-8 pairs of small oblong leaflets covered in fine silky hairs. Solitary yellow five-petalled flowers about 1 cm across appear in leaf axils from spring through autumn. The distinctive fruit is a hard schizocarp that splits into five spiny, woody nutlets, each armed with two sharp divergent spines that easily puncture skin and tires, giving the plant its common names puncture vine and caltrop. Both fruit and whole herb are used medicinally.