A Wei

A Wei is the dried oleo-gum-resin (asafoetida) exuded from the living rootstock and lower stems of giant perennial herbs in the genus Ferula (Apiaceae), principally Ferula sinkiangensis K.M.Shen in Chinese commerce and Ferula assa-foetida L. in the broader Asian and European trade. These plants are robust, monocarpic to polycarpic herbaceous perennials 1-3 m tall with a thick, fleshy, sulphurous-smelling taproot, a stout hollow flowering stem, finely divided pinnatisect basal leaves, and large compound umbels of small yellow flowers, native to the steppes and mountains of Iran, Afghanistan, Central Asia, and western China. To collect the resin, mature roots are exposed and incised; the milky exudate hardens into reddish-brown to yellowish-brown irregular masses or tears with an intensely pungent, alliaceous, persistent odour.