Annuals 20-80 cm tall. Roots yellow, fibrous. Stems erect, subquadrangular, narrowly winged on angles, branched. Leaves sessile, lanceolate to elliptic-lanceolate, 2-6 cm × 3-12 mm, both ends attenuate, veins 1-3. Inflorescences panicles of cymes, spreading branched, many flowered. Flowers 4merous. Pedicel erect, 3-7 mm. Calyx tube 1-2 mm; lobes linear-lanceolate, 6-8 mm, apex acute, midvein 1-3. Corolla white or pale yellow, with brown spots, 8-9 mm in diam., tube 1-2 mm; lobes 4-6.5 mm, apex obtuse and apiculate. Nectaries 1 per corolla lobe, pocket-shaped, with an orbicular scale and many minutely hairy short fimbriae at apex of pocket. Filaments 3.5-4 mm; anthers ellipsoid, ca. 1 mm. Style short, distinct; stigma lobes capitate. Capsules ovoid, 5-7 mm. Seeds brown, ellipsoid, ca. 0.6 mm. Fl. and fr. Aug-Nov.

100-3300 m. Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Yunnan [Bhutan, India, Kashmir, Myanmar, Nepal, Sikkim, Vietnam]