Description from Flora of China
Herbs perennial, 15--45 cm tall. Stems procumbent, simple or branched from base, glabrous or rust-colored pilose. Leaves opposite; petiole 1/5--1/2 as long as leaf blade; leaf blade broadly ovate to suborbicular, 1--3 X 0.9--2.6 cm, strigillose or occasionally glabrescent, densely black glandular striate and punctate, base cordate, apex subacute to obtuse. Pedicel slightly recurved in fruit, 1.5--3 mm, glandular puberulous. Flowers solitary, in axils of upper leaves. Calyx lobes oblong-lanceolate, 4--5 mm, black glandular striate and punctate, decurrent at base, forming a ca. 1 mm long spur, hyaline margined, apex obtuse, cristate; crest ca. 1.5 mm wide. Corolla yellow; tube ca. 3 mm; lobes oblong, 7--8 mm, densely black glandular striate, apex obtuse to obscurely emarginate. Filaments 6--7 mm, lower 1/2 connate into a tube; anthers oblong, dorsifixed, opening by lateral slits, ca. 1.5 mm. Ovary glabrous; style ca. 6 mm. Capsule subglobose, ca. 3 mm in diam. Fl. May-Jun.
* Streamsides; 1000--1600 m. NW Hubei, S Shaanxi, E Sichuan.