Herbs erect. Stems 30-70 cm tall, few branched, densely pubescent. Petiole 0.5-2 cm; leaf blade ovate, 2.5-6 × 1.5-3 cm, blackish or brownish when dry, adaxially densely appressed pubescent, abaxially pubescent, densely so on veins, glandular, base obtuse to rounded, margin double crenate, apex acute to short acuminate, lateral veins 3-paired. Racemes terminal, 6-11(-19) cm, blackish or dark brown when dry, ± interrupted basally; verticillasters many flowered; rachis densely spreading gray pubescent; bracteoles subulate, rigidly ciliate. Pedicel 1-2 mm, densely spreading gray pubescent. Calyx tubular-campanulate, 3-3.5 mm, densely gray pubescent, throat densely white hirsute annulate; teeth subequal, subulate, margin minutely hispid. Corolla purplish or purple, slightly exserted, 4-4.5 mm; lobes subequal, bearded inside. Filaments moniliform barbate. Nutlets subglobose, adaxially ribbed. Fl. Sep-Oct, fr. Oct-Nov.