Description from Flora of China
Herbs perennial, rhizomatous, stoloniferous. Stems erect, 26-30 cm tall, occasionally with long prostrate branches from base. Petiole 0.5-1 mm, densely short hairy; leaf blade lanceolate to triangular-lanceolate, 1.7-3.3 cm × 3-6 mm, base shallowly cordate to subtruncate, margin entire and involute, apex obtuse. Flowers axillary on apical part of stem, secund. Pedicel ca. 4 mm, densely puberulent. Calyx ca. 4 mm, densely pubescent outside, to 6 mm in fruit; scutellum ca. 0.5 mm, to 1 mm in fruit. Corolla purple, 2-2.5 cm, pubescent outside, apically sparsely pilose inside, throat to 8 mm wide; middle lobe of lower lip suboblate, ca. 9 mm wide, margin entire; lateral lobes oblong, ca. 3.5 mm wide. Nutlets yellow-brown, ovoid, ca. 1.25 × 1 mm, tuberculate, adaxially umbonate at base. Fl. Jun-Jul, fr. Jul-Sep.
Riverbanks, marshy areas; 500-1000 m. Hebei, Heilongjiang, Jilin, Nei Mongol [Korea, Mongolia, Russia]