Description from Flora of China
Herbs perennial, 20--40 cm tall. Stems erect, dull brownish red at base, branched above middle, initially strigillose. Leaves opposite, connate-perfoliate, lanceolate, occasionally ovate on upper part of stem, 2--7.5 X 0.6--2 cm, contracted at lower part and then dilated and connate with opposite leaf base, densely strigillose and transparent glandular punctate; midvein raised abaxially, pilose; veins 3 or 4 pairs. Lowest pedicels recurved in fruit, to 2.5 cm, gradually reduced upward, densely strigillose. Flowers solitary, in axils of upper leaves. Calyx lobes lanceolate, ca. 6 mm, enlarging to 1 cm in fruit, densely strigillose, abaxially transparent glandular punctate. Corolla yellow, slightly longer than calyx, deeply parted; tube 1.5--2 mm; lobes broadly ovate, apex obtuse. Filaments connate basally into a 2--2.5 mm high tube, free parts 4--4.5 mm; anthers dorsifixed, opening by lateral slits. Ovary ovoid; style ca. as long as stamens. Capsule brown, subglobose, 4--5 mm in diam., sparsely strigillose on upper part.
* Mountain valleys, woodlands; 900--1100 m. S Anhui, N Jiangxi.