Herb perennial or sometimes biennial. Roots containing purple dye. Stems usually 2-4, sometimes only 1, erect, much branched, 10-25 cm tall, densely spreading long hispid, short strigose. Leaves sessile, spatulate-linear to linear, 1.5-5.5 cm × 3-11 mm, densely hirsute, hairs discoid at base, apex obtuse. Inflorescences crowded; cymes 3-10 cm; bracts linear-lanceolate; flowers heterostylous; calyx lobes linear, 6-10 mm, to 1.5 cm in fruit, long hispid; corolla yellow, tubular-campanulate, pubescent outside; limb 7-12 mm wide; lobes spreading, broadly ovate or semiorbicular, frequently purple spotted; anthers oblong, ca. 1.8 mm; style filiform, apex 2-lobed; stigma reniform. Nutlets light yellow-brown, triangular-ovate, 2.5-3 mm, tuberculate.

Flora of China

The dried root promotes blood circulation, counteracts toxicity, and facilitates eruption of measles, and externally applied for eczema, scalds, and burns.

Jing-Nuan Wu. An Illustrated Chinese Materia Medica. P: 104, Oxford University Press, Inc.2005.