Erect prickly shrub to 50 cm tall. Branches obscurely 4-angled, glabrous, in lower axils with 2 downturned spines about 1 cm long. Petiole 2-3 mm long; blade narrowly obovate, 3.5-9.2 x 0.8-1.2 cm, rigid, spine-tiped at apex, glabrous, dark green with red central vein on upper surface, margin entire. Inflorescence nodding, or erect terminal spike with imbricate bracts; bracts broadly obovate, about 15 x 12 mm, shortly mucronate, basally green, upper half reddish-brown, shortly pubescent with cup-shaped glands scattered over outer surface; bracteoles included in bracts, lanceolate, about 5.5 mm long, spinescent, shortly pubescent with predominantly eglandular trichomes mixed with a few glandular trichomes. Calyx lobes lanceolate, longer pair about 1 cm long, shorter pair about 8 mm long, all spine-tipped, covered with short eglandular trichomes, mixed with cup-shaped glands; corolla entirely pale yellow, 35 mm long, glabrous or sparingly and inconspicuously puberulent. Capsule and seeds not seen.
Naturalized and persistent in many areas of the tropics, where it grows in open woodland habitats, along watercourses, roadsides and in disturbed areas.
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