Perennial, ± aromatic, rhizomatous herb; stems densely hairy or tomentose, to 60 cm high. Basal lvs long-petiolate; upper cauline lvs shortly petiolate or subsessile. Lamina 4-7.5-(14) × 1.5-3-(6) cm, oblong to ovate, ± regularly and closely dentate, puberulent above, greyish tomentulose below; base cordate to truncate; apex obtuse to short-acuminate. Infl. elongating to c. 20 cm, often branched at base; spike with up to c. 20 closely placed verticels; fls ± subsessile; bracts 8-12 mm long, hairy, broad-ovate, reddish to ± purple, acuminate or cuspidate. Calyx 5-7 mm long, purplish, hairy, especially on the prominent veins, and with oil globules, accrescent; teeth triangular, acuminate. Corolla 10-12-(14) mm long, hairy outside; dotted with oil globules, deep purple; upper lip hooded and arched. Stamens included in lower lip, with long connective fertile arms; sterile arm short and wide; filaments short. Nutlets c. 2 mm long, broad-obovoid.