Description from Flora of China
Pleurogyne macrantha Diels & Gilg in Futterer, Durch Asien, Bot. Repr. 3: 17. 1903; Swertia deltoidea Burkill.
Annuals 7-35 cm tall. Stems ascending, angular, few branched from base, glabrous. Basal leaves sessile, lanceolate, ovate-lanceolate, or ovate-triangular, 0.7-2.7 cm × 2-12 mm, base obtuse, apex rounded, midvein distinct. Stem leaves sessile, smaller toward apex, lanceolate, elliptic, or ovate-elliptic, 0.4-2 cm × 3-7 mm, base obtuse, apex acute to obtuse, veins indistinct or only midvein abaxially distinct.
Cymes lax, terminal and axillary. Flowers 5merous. Pedicel spreading to arcuate, to 9 cm, angular, glabrous. Calyx tube 1-1.5 mm; lobes linear to linear-lanceolate, 7-11 mm, base obtuse, margin scabrous, apex acuminate, veins 1-3. Corolla pale blue-purple, with dark blue lines, 2-2.5 cm in diam., tube 1-1.5 mm; lobes oblong to ovate-elliptic, 1.3-2 cm, apex acuminate. Nectary connate at base into a tube pointed outward, apex lamellate, margin lobed. Filaments 8-11 mm; anthers blue, narrowly ellipsoid, 3-3.5 mm. Ovary ensiform to ovoid-ellipsoid, apex triangular acute. Stigma lobes triangular, decurrent to apical part of ovary. Capsules narrowly ovoid-ellipsoid to ellipsoid, as long as persistent corolla. Seeds dark brown, ellipsoid, 0.7-0.9 mm in diam.; seed coat scabrous. Fl. and fr. Aug-Oct.
Beside streams, hillsides, scrub, forests, alpine meadows; 2500-4800 m. Gansu, Qinghai, W Sichuan, E Xizang [Bhutan, Nepal, Sikkim].