Description from Flora of China
Plants perennial. Stems 1 to few, 30-65 cm, pilose toward base, densely villous upward. Petiole 2-13 cm; leaf blade elliptic-lanceolate to oblong-ovate, 2-22 × 2-9 cm, glabrescent or ± hairy, abaxially subglabrous, base rounded to subcordate, rarely subtruncate, margin irregularly crenate to dentate, apex obtuse to subacute. Inflorescences densely villous, glandular pilose; verticillasters 2-4-flowered, widely spaced, in racemes or panicles; bracts ovate to broadly ovate, 4-10 × 2.5-8 mm. Pedicel 4-5 mm. Calyx campanulate, 0.9-1.5 cm, densely glandular villous, yellow-brown glandular, 2-lipped to ca. 1/3 its length; upper lip broadly triangular-semicircular, ca. 3 × 6 mm; lower lip slightly longer, ca. 4 × 6 mm; teeth triangular, apex acute. Corolla purple-brown, chestnut brown, or dark purple, 3-3.2 cm, pilose; tube obliquely pilose annulate inside, ca. 2.6 cm, zigzag toward base, curved upward beyond calyx, to 1 cm wide at mouth; upper lip ovate, ca. 6 mm, erect, falcate/slightly galeate; lower lip triangular, ca. 0.8 × 1.4 cm; middle lobe obcordate, ca. 4 × 6 mm; lateral lobes semicircular, ca. 5 mm wide. Filaments ca. 7 mm; connectives ca. 5 mm, arms subequal. Nutlets obovoid, ca. 3 mm, apex rounded. Fl. May-Sep.
The forms castanea, glabrescens, pubescens E. Peter (Acta Horti Gothob. 9: 134. 1934), and tomentosa E. Peter (Repert. Spec. Nov. Regni Veg. 39: 181. 1936) have been differentiated largely on differences in hairiness of leaf surfaces.
Forests, hillsides, grasslands; 2500-3800 m. Sichuan, Xizang, Yunnan [Nepal]