Zi Wan

Aster tataricus (Tatarian aster) is a tall, robust herbaceous perennial in the Asteraceae family, growing 1-1.5 m tall, native to grasslands, meadows, and forest margins of northeastern China, Korea, Japan, Mongolia, and the Russian Far East. Its rootstock is a short, knotty, horizontal rhizome bearing dense clusters of slender, twisted, purplish-brown fibrous roots that constitute the medicinal Zi Wan. The erect, ribbed, finely hairy stems bear alternate leaves: basal leaves long-petioled, elliptic-spatulate, 20-40 cm long, with toothed margins, withering by flowering time; stem leaves smaller, lanceolate, sessile. Numerous showy radiate flower heads 2.5-4 cm across, with violet-blue to lavender ray florets and yellow disc florets, are arranged in flat-topped corymbose panicles in late summer and autumn (POWO; Wikipedia).