Perennial, herbaceous. Stems sturdy, quadrangular, leafy, erect, several, up to 1 m, below densely eglandular pilose or villous, above with a dense indumentum of glandular hairs and sessile oil globules. Leaves up to 14 x 10 cm, triangular-ovate to oblong-ovate, whitish below, usually densely arachnoid with eglandular and glandular hairs and numerous sessile oil globules, margin sinuate, lobed or regularly crenate, truncate or cordate at base, acute at apex; lower leaves with a petiole to 7 cm, upper cauline leaves sessile, amplexicaul. Inflorescence showy, wide paniculate; verticillasters 4-6-flowered, clearly separated. Bracts broad ovate, abruptly acuminate c. 10 x 10 mm, often violet tinged; bracteoles present. Pedicels to 3.5 mm, erect-spreading. Calyx campanulate, in flower to 10 mm expanding slightly in fruit, densely covered with eglandular and glandular hairs and sessile oil globules, often lilac coloured; teeth of upper and lower lips shortly mucronate. Corolla c. 25 mm long, with a prominent falcate lilac upper lip and a yellowish lower lip; tube c. 10 mm, ventricose, squamulate and invaginated. Lower thecae adhering, sterile, dolabriform. Nutlets ovoid-trigonous, brown with darker veins, c. 2.5 x15 mm.