Annuals 10-15 cm tall. Roots yellow, stout. Stems erect, 2-3 mm in diam., subquadrangular, narrowly winged on angles, branched. Leaves sessile, linear to linear-lanceolate, ca. 3.5 cm × 6 mm, both ends attenuate, midvein prominent. Inflorescences panicles of cymes, many flowered, spreading. Flowers 5merous. Pedicel erect, to 2 cm, 4angled. Calyx tube 1-1.5 mm; lobes linear, to 1.5 cm, apex acuminate, midvein distinct. Corolla blue-purple, with dark blue veins, 1.5-2 cm in diam., tube 1-1.5 mm; lobes lanceolate, 0.9-1.6 cm, apex acuminate. Nectaries 2 per corolla lobe, radially elongated, with a narrow scale, and raised margin with many long compound fimbriae. Filaments 6-8 mm; anthers narrowly ellipsoid, 2.5-3 mm. Style indistinct; stigma lobes capitate. Fl. Aug-Sep.

Beside streams, hillsides, scrub, forests; 500-1600 m. Hebei, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi [Japan, Korea].