Herbs erect. Stem solitary, 0.5-1.5 m, retrorse strigose, flexuous, leafless toward base. Petiole slender, to 8 cm; leaf blade elliptic to oblong-ovate, 3-15(-30) × 1.5-8.5(-14) cm, adaxially ± minutely hispid, abaxially strigose, base rounded to subtruncate, margin inconspicuously serrate to crenate-serrate, apex acute to acuminate. Verticillasters many flowered, globose, ca. 3 cm in diam., surrounded by few bracteoles at base; bracteoles subulate, ca. 6 mm, shorter than calyx, hirtellous. Flowers sessile. Calyx tubular in flower, abruptly spreading at mouth, enlarged and red in fruit, leathery, densely hirtellous or minutely hispid, glabrescent, inconspicuously veined, tube ca. 7 mm; teeth subequal, needlelike to triangular, 2-4 mm. Corolla yellow or yellowish, less often whitish, ca. 1.7 cm, ± hirtellous on apical parts of tube and limb outside, pubescent annulate inside, upper lip oblong, entire. Nutlets black, triquetrous, obovoid, apex rounded, glabrous. Fl. Jun-Aug, fr. Aug-Dec.