Plants highly branched shrubs, to 2 m tall; branches terete, covered with appressed pubescence; nodes densely pubescent. Leaves sessile to petiolate; petioles (0)0.3-10 mm long, pubescent; blades 2-12.5 cm long, 1-4 cm wide, bases attenuate to cuneate and decurrent, tips acute to acuminate, both surfaces villous, especially along the veins; secondary veins 4-7 on each side. Inflorescences axillary, shortly pedunculate, dense spikes or cymes with 1-5 flowers; bracts absent; bracteoles variable, linear to linear-lanceolate, 2-8 mm long. 0.5-1.5 mm wide, 3-7-veined, margins usually spiny but sometimes bristley or pilose and becoming spinescent with age, tips acuminate. Calyces deeply 4-lobed, outer 2 lobes ovate to narrowly elliptic or lanceolate, 1,2-2.5 cm ong, 0.5-1.3 cm wide, reticulately veined, hairy or glabrescent, margins spiny, tips mucronate, inner lobes 6-12 mm long, 1-veined, margins scarious; corollas purplish blue, 4.5-6.5 cm long, outer surfaces pilose, tube 3.5-4 cm long, narrowly cylindrical at the base, gradually widened distally, lobes 1.5- 2 cm long, subequal; stamens 4, in two pairs, filaments pilose twoards the base, staminode 1, filaments sparsely pilose; ovaries glabous, 4-seeded; styles 2.5-4* cm long, simple, slightly thickened in the stigmatic regions. Capsules 1.2-2 cm long, glabrous; seeds 4-5 mm lon, about 4 mm in diameter, globose to ovoid, appressed hairy.
Barleria cristata is native from Pakistan east through the southern Himalayas and southern Asia to China and the Philippines. It is often cultivated as an ornamental plant. It is also used as a medicinal plant.
Hu, Jiaqi, Yeunfei Deng, and Thomas F. Daniel. 2011. Barleria in Wu Zhengyi, Peter H. Raven, and Hong Deyuan (Editors), Flora of China 19: 468 - 469.
Malik, Kamal A. and Abdul Ghafoor. 1988. Acanthaceae. In E. Nasir and S.I. Ali (Editors), Flora of Pakistan vol 188: 1-79.
*There was one major difference between the two descriptions: in the Flora of Pakistan, style length was given as about 4 cm, in the Flora of China as about 2.5 cm.