Hua Jiao

Zanthoxylum bungeanum, the Sichuan or Chinese prickly ash, is a deciduous, prickly shrub or small tree in the Rutaceae, native to central and western China and widely cultivated for its pungent fruit pericarp, known as Hua Jiao. It grows 3 to 7 meters tall, with greyish-brown bark studded with prominent, broad-based corky prickles and similar shorter prickles on the young branches. The alternate, pinnately compound leaves bear 5 to 13 ovate to ovate-lanceolate leaflets 2 to 7 cm long, with finely crenulate margins, distinct translucent oil glands and a rachis that is conspicuously winged or armed with small prickles. The plant is dioecious; flowers are small, yellow-green, four- to eight-parted, arranged in dense, short terminal panicles in spring. The fruit is a small, globose follicle 4 to 5 mm across, splitting at maturity to expose a shiny black seed; the dark red-brown, rugose pericarp is highly aromatic, contains hydroxy-alpha-sanshool and other amide alkaloids, and is responsible for the characteristic numbing-pungent quality of the spice.