Description from
Flora of China
Annuals 15-35 cm tall. Roots yellow, stout. Stems erect, subquadrangular, narrowly winged on angles, branched. Leaves subsessile, lanceolate, linear-elliptic, or spatulate, 0.7-2.6 cm × 1-7 mm, base narrowed, apex acute, midvein distinct. Inflorescences panicles of cymes, many flowered, spreading. Flowers 5merous. Pedicel erect, 7-11 mm, slender. Calyx tube 1-1.5 mm; lobes linear-lanceolate, 3-6 mm, apex acuminate, midvein distinct. Corolla white, rarely pale blue, 1-1.2 cm in diam., tube 1-1.5 mm; ovate-lanceolate to ovate, 5-9 mm, apex obtuse. Nectaries 2 per corolla lobe, radially elongated, with a narrow scale and raised margin with many 3-5 mm fimbriae. Filaments 4-5 mm; anthers ellipsoid, 1-1.5 mm. Ovary ovoid, 4.5-5.5 mm. Style indistinct; stigma lobes capitate. Fl. Oct-Nov.
* Edges of cultivated land, grasslands, forests, valleys; 100-1600 m. Anhui, Fujian, Guangxi, Hunan, Jiangsu, Jiangxi, Zhejiang.