Roots slender, cordlike. Rhizome branched, woody. Stems many, branched near base, ascending, purplish brown, 5-25 cm, woody near base, glabrous. Leaves opposite, sessile, usually with brown spots, broadly ovate to suborbicular, 1.5-2 × 1.5-2 cm, margin entire or inconspicuously dentate, apex obtuse, tip acuminate. Cyme umbel-like, crowded, 2-3 cm wide. Sepals free, lanceolate, ca. 2 mm. Petals purplish red, ovate-lanceolate, ca. 5 mm, apex acute. Stamens shorter than petals; filaments reddish; anthers purple. Nectar scales ovate-oblong, apex emarginate. Follicles erect, 3-4 mm, base narrow, apex shortly beaked. Seeds brown, lanceolate. Fl. Jul-Aug.