Description from Flora of China
Justicia canescens Lamarck, Tabl. Encycl. 1: 41. 1791.
Herbs 10-20 cm tall, annual, creeping, sprawling, prostrate, or decumbent. Stems subterete, villous, often rooting at nodes. Petiole 0.2-3(-4) cm, villous; leaf blade elliptic to ovate, 1-2.2 × 0.4-1.2 cm but basal ones sometimes 6-12 × 3.5-5 cm, both surfaces villous, secondary veins 3-7 on each side of midvein, base cuneate, margin entire, apex acute. Spikes 1.5-4 cm; bracts elliptic, 6-7.5 × 3-4 mm, 5-7-veined. Calyx abaxial lobe ca. 2 × 0.6 mm, apex 2-lobed; adaxial lobe ca. 3 × 1 mm; lateral lobes ca. 2 × 0.5 mm. Corolla bluish purple or white, externally glabrous; tube cylindric for ca. 1.5 mm, contracted near midpoint then expanded into throat; lower lip ca. 2.3 mm; upper lip ca. 2 mm. Stamens inserted at base of throat; filaments ca. 0.5 mm, glabrous. Ovary glabrous; ovules 4-8 per locule. Capsule ca. 5 × 2 mm, 8-16-seeded. Seeds broadly ellipsoid, granulate. Fl. Oct-Mar, fr. Mar-May. 2n = 34 + ß, 36.
Wet places, open forests; 400-2000 m. Guangxi, Yunnan [Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Thailand, Vietnam; Africa, Madagascar].