Description from Flora of China
Herbs to subshrubs, weak to erect, to 60[-75] cm tall, usually drying partly to wholly red; stems glabrous or with pilosulous lines. Leaves in subequal pairs; petiole 0.5-2 cm, glabrous or subglabrous; blade drying thinly papery, lanceolate-elliptic, ovate-elliptic, or elliptic-oblong, 5-11(-20) × 2.5-4(-8) cm, glabrous on both surfaces or sparsely pubescent adaxially, base cuneate to obtuse, margins entire or undulate, apex acuminate to caudate; secondary veins 7-10 pairs; stipules caducous, not seen. Inflorescence congested-cymose, many flowered, often pendulous later becoming erect, glabrescent or axes sometimes puberulent to pilosulous in lines; peduncle 1-1.5[-3] cm; axes short; bracts linear-lanceolate, 6-9 mm. Flowers perhaps homostylous, on pedicels 1-1.5 mm. Calyx glabrous to puberulent or densely pilosulous; hypanthium submitriform, ca. 1.5 mm, 5(or 10)-ribbed; lobes ovate-triangular to lanceolate-triangular, usually slightly unequal, 1.4-1.8 mm, with 1 gland in each sinus. Corolla pink or white, tubular-funnelform and swollen at base, outside glabrous; tube 7-7.5[-10] mm, inside glabrous or villous; lobes ovate, ca. 2.5 mm, dorsally narrowly keeled. Capsules mitriform, [2-3.5 × 6-9 mm], glabrous to puberulent or pilosulous. Fl. Jul-Oct.
This species has apparently been distinguished based primarily on its distinctive purple-red drying color; it is characterized further in the key to species here.
Measurements in brackets are taken from the description of this species by Deb and Mondal (Bull. Bot. Surv. India 39(1-4): 120-122. 1997), where this species is reported to flower throughout the year and grow from middle elevations up to 2400 m. H. S. Lo (in FRPS 71(1): 145-146. 1999) did not posit the floral biology but described the flowers similarly to Deb and Mondal as essentially homostylous, with the anthers and stigmas both positioned near the middle of the corolla tube.
Broad-leaved forests; ca. 2000 m or more. Guizhou, Xizang (Mêdog), Yunnan [Bhutan, NE India, Myanmar, Nepal].