Swertia diluta (Turcz.) Benth. & Hook. fil.

Annuals 20-70 cm tall. Roots yellow, stout. Stems erect, 2-4 mm in diam., subquadrangular, narrowly winged on angles, branched. Leaves sessile, linear to linear-lanceolate, 1-4.5 cm × 2-9 mm, both ends attenuate, midvein prominent. Inflorescences panicles of cymes, many flowered, spreading branched. Flowers 5merous. Pedicel erect, to 1.5 cm, 4angled. Calyx tube 1-1.5 mm; lobes linear, 6-12 mm, apex acuminate, midvein distinct. Corolla white, pale blue, or pale lilac, 1-1.5 cm in diam.; tube 1-1.5 mm; lobes elliptic-lanceolate, 6-11 mm, apex acute. Nectaries 2 per corolla lobe, radially elongated, with a narrow scale and raised margin with many simple fimbriae. Filaments 6-8 mm; anthers ellipsoid, 1.5-2 mm. Style indistinct; stigma lobes capitate. Capsules ovoid, 1-1.2 cm. Seeds dark brown, ellipsoid, 0.6-0.8 mm; seed coat warty. Fl. Aug-Oct.

Gansu, Hebei, Heilongjiang, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, N Sichuan, Xinjiang [Japan, Korea, Mongolia, Russia (Siberia)]

100-3100 m.