Stems 50-80 cm, stiff, with long internodes, with few leaves below, ± leafless above, acutely quadrangular. Leaves c. 2040 x 5 mm, attenuate into a subabsent petiole, apically spinulose. Verticillasters clearly distant, 3-5. Bracts 3-partite, equal in length to calyx, ending in rigid spines. Calyx pale green; tube c. 6.5 mm; limb of 7-9 spreading spiny teeth of unequal length, longest c. length of tube, ± horizontally spreading. Corolla white; tube c. 7-8 mm; upper lip linear-oblong, 8-9 mm, entire.