Description from Flora of China
Shrubs to small trees, unarmed. Raphides presumably absent. Leaves opposite, apparently without domatia or these infrequent and rudimentary; stipules persistent at least near stem apex, interpetiolar, generally triangular, 2-lobed. Inflorescences terminal and sometimes also in uppermost leaf axils and appearing sessile and tripartite, cymose with higher order axes often scorpioid, many flowered, pedunculate, bracteate with bracts persistent or caducous. Flowers sessile or subsessile, bisexual, distylous. Calyx limb deeply 5-lobed, on 1 or several flowers of an inflorescence with 1 white, elliptic or ovate calycophyll. Corolla orange-yellow to orange, salverform with tube slender then abruptly swollen in upper part, inside pubescent at least in throat; lobes 5, notably acuminate, in bud valvate-induplicate with tips pressed together and ascending. Stamens 5, inserted in upper part of corolla tube, included in long-styled form, partially exserted in short-styled form; filaments short; anthers apparently basifixed. Ovary 2-celled, ovules numerous in each cell on axile peltate placentas; stigmas 2, linear, exserted in long-styled form or included in short-styled form. Fruit capsular, ellipsoid to obovoid, slightly flattened perpendicular to septum, loculicidally dehiscent through apical half, woody, with calyx limb persistent, with calycophylls persistent; seeds numerous, small, angled.
This species was long included in Mussaenda, but morphological and molecular studies support its separation from that genus. Its morphology was studied by Puff et al. (Bull. Jard. Bot. Natl. Belg. 62: 35-68. 1993). Its lack of raphides has not been described but is presumed based on the classification of this genus by various authors in Isertieae.
One species: SW China, Laos, N Myanmar, N Thailand, N Vietnam.
(Authors: Chen Tao (陈涛); Charlotte M. Taylor)