Description from Flora of China
Trees, unarmed. Raphides absent. Leaves opposite, with domatia; stipules caducous, interpetiolar, triangular, acute. Inflorescences terminal, corymbose to paniculiform, many flowered, pedunculate, bracteate with bracts reduced. Flowers pedicellate, bisexual, monomorphic, fragrant. Calyx limb 5-lobed nearly to base, with lobes imbricate in bud, some flowers of most inflorescences with 1 lobe expanded into a white petaloid calycophyll. Corolla white or yellow, funnelform with tube notably narrowed near base, glabrous inside; lobes 5, imbricate in bud. Stamens 5, inserted below corolla throat, included; filaments developed, tomentose; anthers dorsifixed, included. Ovary 2-celled, ovules numerous in each cell on peltate axile placentas; stigma capitate or shallowly 2-lobed, included. Fruit capsular, oblong-cylindrical to fusiform with disk portion shortly prolonged into a rounded beak, septicidally dehiscent from apex in apical half, woody, with calyx limb deciduous except with calycophyll sometimes persistent; seeds numerous, medium-sized, fusiform, flattened, winged; testa spongy, reticulate-areolate; albumen rich; embryo minute; cotyledons cylindric.
Emmenopterys is currently known only from moist temperate E Asia, with its range wholly inside China, but fossils of the genus are known from W North America; Latham and Ricklefs (in Ricklefs & Schluter, Spec. Diversity Ecol. Communities, 294-314. 1993) discussed the biogeography and putative history of this distribution.
Emmenopterys henryi is considered a rare species of conservation concern in China. Its habitat, population status, and distribution were studied by Chen et al. (Acta Bot. Yunnan. 29: 461-466. 2007) in one site, where the population appears to be declining; additional studies are cited there, and its classification as a Grade II Chinese National Protected Wild Plant was reviewed by Liu (Gansu Sci. Technol. 19(10): 151-152. 2003).
● One species: China.
(Authors: Chen Tao (陈涛); Charlotte M. Taylor)