Description from Flora of China
Asystasia pauciflora Nees in Wallich, Pl. Asiat. Rar. 3: 90. 1832; Codonacanthus acuminatus Nees; Leptostachya repanda Q. H. Chen.
Herbs 20-60 cm tall, much branched or unbranched. Stems 4-angled, sulcate, 2-fariously pubescent. Petiole 3-15 mm, puberulent or glabrous; leaf blade elliptic, ovate, or lanceolate, (2-)4-12 × (0.5-)1.5-4.5 cm, thin, abaxially pale green and glabrous or sparsely pubescent on major veins, adaxially green, glabrous or with few large-celled hairs, and with numerous cystoliths, secondary veins 5-7 on each side of midvein, base rounded, cuneate, or attenuate and decurrent onto petiole, apex acute or acuminate. Racemes simple or terminal ones usually forming a panicle up to 15 cm; rachis puberulent; bracts lanceolate to linear, 1-2.5 mm, puberulent; bracteoles lanceolate, 1-2 mm, puberulent. Pedicel 1-7 mm, puberulent. Calyx 2.5-4 mm; lobes lanceolate, puberulent. Corolla white with purple spots at base of lower lip, 6.5-10 mm, glabrous; tube basally cylindric for 1-2 mm and 1-1.5 mm wide then abruptly widened to 3.5-6.5 mm at mouth; lobes of lower lip 3.5-5.5 × 2-3.5 mm. Staminal filaments ca. 2.5 mm, glabrous; anther thecae 1.2-1.4 mm. Ovary glabrous; style 4-6.5 mm. Capsule 1-1.9 cm, glabrous. Seeds 2-3 mm. Fl. and fr. Aug-Apr.
Evergreen broad-leaved forests, wet places in ravines; below 100-1500 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Jiangxi, Taiwan, Yunnan [Bhutan, Cambodia, India, Japan, Myanmar, Thailand, Vietnam].