Annual herbs with a short rootstock; stem erect, 15-30 cm high, obtusely 4 angular, pubescent with retrorse hairs, diffusely branched. Leaves opposite, 0.7-4.2 x 0.35-1.6 cm, oblong to ovate-oblong, cuneate to tapering to base, obtuse, faintly serrulate, glabrous and copiously dotted with oil globules on both surfaces; petioles 1-2.2 cm long. Racemes 3-5 cm long; verticils distant. Floral leaves linear-oblong, with a concave, glandular receptacle at base. Calyx tube 2.5 mm long, subglabrous to sparsely pubescent without, glabrous within; upper lip broadly ovate-oblong, to 8 mm long in fruit, slightly longer than the lower; lateral lobes of lower lip bimucronate or truncately serrated, median ones spinous-acuminate. Corolla 6-7 mm long, puberulous without, pinkish-white; upper lip 3 mm long, lower equally long. Stamens much exserted, ± twice length of corolla; filaments glabrous. Nutlets globose, 1.5 mm long, smooth, mucilaginous when wetted.
