A stout, suffrutescent, strigose-hispid, upto 80 cm tall herb, armed with 6 axillary, 2-3.5 cm long, straight or curved thorns at each node. Leaves in pseudowhorls of 6, outer 2 larger, sessile, lanceolate or oblong-lanceolate, (4-) 5-12 (-15) x 1.5-2.5 cm, white-hairy, margins inconspicuously dentate, base cuneate, acute at the apex. Flowers in axillary, whorled fascicles, purplish-blue, c. 2.5 cm long; bracts lanceolate, 2-2.5 cm long, hairy; bracteoles linear, 6-8 mm long, pilose. Calyx 4-lobed, lobes unequal, lanceolate, acute, outer ones longest, 2-2.2 cm long, limb 2-lipped, 5-lipped, 5-lobed, lips subequal, upper lip 2-lobed, lower trilobite, lobes obtuse. Stamens 4, all fertile; anthers oblong, c. 2.5 mm long. Ovary oblong, 8-ovuled, hairy at tip; style filiform, upto 2.5 cm long. Capsule oblong, shorter than calyx, glabrous, 4-8-seeded. Seeds orbicular, c. 3 mm across, on long curved retinacula.