Perennial herb. Stems erect, 30-80 cm, usually branched, quadrangular, glabrous to minutely pilose with retrorse eglandular hairs, sometimes densely pilose-villous below inflorescence axis, leafy. Leaves green, triangular-ovate to elliptic, 30-60 x 20-30 mm, regularly crenate to senate, broad truncate to cordate, acute, abaxially with a thin indumentum of short eglandular hairs and with sessile oil globules; petiole up to 4 cm on lowermost leaves, decreasing above. Inflorescence of mainly terminal continuous congested oblong spikes up to 8 x 2 cm, subtended by small uppermost stem leaves. Outer bracts up to 4 mm broad, often purplish and showy, sometimes yellowish, broad ovate or trullate, long attenuate; innermost bracts linear-filiform as long as calyx. Calyx 6-8 mm, slender, tubular, almost glabrous to finely glandular-papillose, with or without oil globules; throat slightly oblique, villous within; teeth unequal, linear triangular, aristate, as long as tube. Corolla mauve to lilac-blue or white, 12-14 mm; tube exserted, curved; upper lip ± straight; lower lip shorter than upper. Nutlets (few seen) 1.3 x 0.9 mm, brown, broad oblong, rounded, minutely granular, matt with a transverse basal areole.