Young branchlets rusty-tomentose with verticillate-branched hairs, older ones glabrous; internodes 1/2–5 in. long. Leaves opposite, elliptic or suborbicular, rounded at the apex, cordate or subcordate at the base, 1–2 1/4 in. long, 1–2 1/4 in. broad, glabrous and finely reticulate on the upper surface, densely brownish-tomentose on the lower; lateral nerves about 5 on each side, slightly raised on the upper surface; petiole 3–7 lin. long. Heads axillary, fascicled, 4-flowered; peduncle 3–4 1/2 lin. long, rusty-tomentose; bract broadly elliptic or ovate, very concave, 1 1/4–1 3/4 lin. long, 1 1/8–1 1/2 lin. broad, rusty-tomentellous outside. Receptacle and calyx together cupular, 1 5/8–2 1/4 lin. long, shortly adpressed-pilose above, basal villous band 1 1/4–1 1/2 lin. long. Calyx shortly and sparingly ciliate, 1–1 3/8 lin. long. Corolla about 2 in. long; tube 8 1/2–9 1/2 lin. long, basal swelling clavate, 2–2 1/2 lin. long, glabrescent below, very long-villous in the upper part; lobes about 1 1/4 in. long, reflexed above the insertion of the stamens. Filaments inserted 2 1/2–3 1/2 lin. above the base of the corolla-lobes, 8 1/2–10 lin. long; anthers linear, 1 3/4–2 lin. long, biapiculate. Disc crenately 5-lobed, 1/8 lin. high, glabrous. Stigma ellipsoid, 3/8 lin. long.