Plant erect; stem smooth, glabrous; leaves opposite, linear-lanceolate or narrowly obovate, rigidly coriaceous, glabrous to subglabrous, dark green with midrib red obove, pale beneath; shortly petiolate; 2 stipular spines in leaf axils; flowers in 5-8 cm long, erect, terminal spikes; bracts broadly obovate, green with purple tinge in upper half and many, small, cupular, glands on the back of the lower half, shortly pubescent; calyx campanulate or tubular, segments unequal, shortly pubescent; corolla yellow, bilipped, tube 3 cm, spreading upward, lobes-5, subequal, elliptic or ovate, imbricate in bud; stamens 4, 2-shorter ones fertile, anther 2-celled, oblong, other 2 with small, rudimentory anthers with few pollen grains, fifth reduced to short filament; disc large, cupular; ovary 2-celled, style long, slender; stigma bifid or subentire; capsules ovoid, ellipsoid or obovoid, 2-4 seeded, attached below the middle; seeds compressed, glabrous or silky, with appressed hairs.