Description from Flora of China
Mazus angusticalyx P. C. Tsoong; M. bodinieri Bonati.
Perennials, 10-30 cm tall, white to pale rusty villous. Primary root 2-4 cm. Stems terete, slender, rigid, usually woody and much branched at base, erect or procumbent and ascending, rooting from nodes. Basal leaves few, caudate. Stem leaves opposite or upper ones alternate; petiole to 1 cm on lower leaves, decreasing in length to lacking upward; leaf blade obovate to obovate-spatulate, 1-4 cm, base tapering, margin incised-serrate. Racemes terminal, lax, to 20 cm; bracts subulate. Pedicel slender, almost as long as calyx. Calyx campanulate, 5-8 mm in fruit, less than 1 cm in diam., veins 10; lobes triangular-lanceolate, as long as tube, margin and veins ciliate, apex acute. Corolla white or light purple, 0.8-1.2 cm; lateral lobes of lower lip rounded and entire, middle lobe narrower and longer and with an emarginate apex; upper lip lobes narrowly acute. Ovary long hirsute. Capsule light yellow, ovoid, small, long hirsute. Fl. May-Jun, fr. Jul-Aug.
* Mountain slopes, trailsides, grassland; 700-2300 m. Guangxi, Guizhou, Hubei, Hunan, S Shaanxi, Sichuan.