Herbaceous perennial with a thick woody rhizome. Stems 50-100 cm, erect, branched, forming clumps up to 80 cm across, quadrangular, finely papillose glandular with scattered villous hairs especially near base. Leaves 15-70 x 10-40 cm, narrow to broad ovate, broad cuneate to cordate, crenulate to serrate, acute, eglandular pubescent, below with numerous sessile oil globules; petiole on lower leaves to 25 mm, decreasing above. Inflorescence of separated many-flowered verticillasters, lowermost pedunculate in wills of upper leaves, upper sessile and approximating. Bracts linear, 1/2 as long to as long as calyces. Pedicels absent to 1.5 mm. Calyx 7-8 mm, almost straight, green or purplish, with eglandular hairs, papillose glands and sessile oil globules; throat slightly oblique; teeth somewhat unequal, triangular-subulate, longest to 3 mm. Corolla pale blue or mauve, c. 15 mm; tube slightly curved, exserted, widest at throat; upper lip bilobed, straight; lower lip ± white, flecked blue. Anthers violet. Nutlets c. 2 x 0.8 mm, ellipsoid, chestnut brown, ± trigonous, apically rounded, minutely granular with a small basal bilobed areole.