Xiang Fu

Cyperus rotundus (Xiang Fu, nut grass, purple nutsedge) is a perennial sedge in the Cyperaceae family, growing 15 to 60 centimeters tall from a complex underground system of slender wiry stolons that link a chain of small, hard, ovoid to fusiform tubers (the medicinal Xiang Fu), each 1 to 3 centimeters long, externally dark brown to blackish with persistent fibrous scales and conspicuous transverse rings, internally pale yellowish-brown with a strong, sweet-pungent, characteristic aroma. The stems are sharply triangular in cross section (a defining feature of Cyperus) and unbranched, bearing at the base a tuft of glabrous, grass-like, linear leaves with prominent midribs. The inflorescence is a terminal umbel-like compound anthela of two to six unequal rays, each bearing reddish-brown to purplish-brown linear spikelets 1 to 3 centimeters long, subtended by leafy involucral bracts that exceed the inflorescence. Native across much of the warm-temperate, subtropical, and tropical world and a globally widespread agricultural weed.