Stems: erect, leafy. Leaves: ovate-lanceolate, sharply cut-toothed. Flowers: in whorls, crowded in a terminal spike.
The leafy erect stems of this plant are crowned with dense whorled spikes of small purple-blue flowers, the upper lip of the small slender corolla is arched and notched, the lower one being three-cleft, with the large middle lobe again two-cleft or notched at the end. The leaves are long-shaped and very sharply toothed, the lower ones being petioled and the upper sessile.