Perennials, more than 60 cm tall. Roots stout, fleshy. Stems obscurely quadrangular, hollow, glabrous, white pilose, or glandular pilose. Leaves opposite; petiole to 5 cm, narrowly winged; leaf blade ovate to ovate-orbicular, 5-9 cm, thin, abaxially puberulent on veins, adaxially glabrous or sparsely hairy, base rounded, cordate-truncate, or rarely broadly cuneate, margin unequally double serrate. Cymes axillary or terminal, 1-3-flowered, rarely 5-flowered; peduncle slender, more than 3 cm. Pedicel slender, more than 3 cm, glandular pilose; bracts large, foliaceous. Calyx ca. 5 mm; lobes narrowly ovate to orbicular-ovate, apex obtuse to acute, margin membranous and more conspicuous in fruit. Corolla purple-red, 1-1.2 cm; tube ovoid-globose; lower lip lobes rounded, middle lobe smaller than other lobes; upper lip 2-3 mm longer than lower lip, lobes 1.5-2 mm, with overlapping margins. Stamens slightly shorter than lower lip; staminode subglobose. Ovary slightly shorter than style. Style 3-4 mm. Capsule narrowly ovoid, 9-10 mm. Fl. Jun-Jul, fr. Aug.
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