Description from Flora of China
Onosma oblongifolium W. W. Smith & Jeffrey; O. paniculatum var. hirsutistylum Lingelshiem & Borza.
Herbs biennial, rarely perennial, 40-80 cm tall, blackened after drying. Stems single, not branched, 5-10 mm in diam. at base, spreading hispid and densely strigose, hairs discoid at base. Basal leaves linear-lanceolate or oblanceolate, 10-12 × 1-2.5(-3) cm, base attenuate, apex acuminate. Upper and middle stem leaves lanceolate or ovate-triangular, 3-7 × 1-2 cm, base hastate, ± clasping, apex acuminate. Inflorescences terminal, elongated racemose after anthesis; bracts triangular. Pedicel slender, 0.7-1.7 cm. Calyx 7-8 mm, enlarged in fruit. Corolla blue-purple, becoming dark red, tubular-campanulate, 1.2-1.4 cm, densely strigose outside, strigose only along lobe midvein inside; throat 5-6 mm wide; nectary ca. 0.5 mm, densely villous; lobes broadly triangular, margin revolute. Filaments decurrent, 4-5 mm, pubescent, inserted 3-4 mm above base of corolla tube; anthers laterally united, ca. 7 mm, included or slightly exserted, apex sterile, ca. 2 mm. Nutlets dark brown, 2-3 mm, not shiny, tuberculate. Fl. and fr. Jun-Sep.
The roots, which contain a purple dye, are used as a substitute for Lithospermum erythrorhizon in Chinese medicine.
Arid slopes, forest margins; 2000-2300 m. W Guizhou, SW and W Sichuan, C and NW Yunnan [Bhutan, NE India]