Swertia tenuis T. N. Ho & S. W. Liu

Annuals 8-30 cm tall. Roots yellow, slender, fibrous. Stems erect, slender, branched from middle. Basal leaves withered at anthesis. Stem leaves sessile; lower leaves oblong to elliptic, 0.9-1.5 cm × 1.5-2.5 mm, base narrowed, apex obtuse, midvein distinct; middle to upper leaves linear to linear-lanceolate, 5-12 × 1-2 mm, base narrowed, apex obtuse, midvein distinct. Inflorescences panicles of cymes, many flowered. Flowers 5merous. Pedicel erect, filiform, 4-12 mm. Calyx tube ca. 0.5 mm; lobes linear, 2.5-4 mm, apex acuminate, midvein indistinct. Corolla pale blue, 3-5 mm in diam., tube ca. 0.5 mm; lobes ovate-oblong to ovate-lanceolate, 4-6 mm, apex acute. Nectaries 1 per corolla lobe, cupular, with a narrow scale, and few long fimbriae. Filaments ca. 3.5 mm; anthers ellipsoid, ca. 0.3 mm. Style short, distinct; stigma lobes capitate. Capsules ovoid, ca. 5 mm. Seeds light brown, subglobose, ca. 0.3 mm. Fl. and fr. Aug-Nov.

S Sichuan, NW Yunnan.

* Grassland slopes, forests; 1200-3500 m.

Swertia gracilis Franchet (1899), not Kunth (1818).