Trees, often large, unarmed, terrestrial, without raphides in the tissues, trunk often with buttresses and fissued bark. Leaves opposite, petiolate, entire, with higher-order venation not lineolate, with pubescent domatia; stipules variously interpetiolar, caducous, triangular, acute, and convolute in bud (Subg. Chimarrhis) or shortly fused into a tube, persistent, ligulate to ovate, acute to rounded, and imbricated in bud (Subg. Pseudochimarrhis). Inflorescences axillary at nodes below stem apex, cymose, multiflowered, pedunculate, bracteate or with bracts reduced. Flowers subessile to pedicellate, bisexual, homostylous, protogynous, apaprently diurnal; hypanthium turbinate to ellipsoid; calyx limb reduced or developed, (4)5(6)-lobed, sometimes with 1 white to pale green calycophyll on some flowers; corolla funnelform to campanulate, white to pale green, internally pubescent in middle of tube, lobes (4)5(6), ligulate to ovate, thinly imbricated in bud, without appendages; stamens (4)5(6), inserted in upper part of corolla tube, anthers ellipsoid, dorsifixed, opening by linear slits, without appendage, exserted; ovary 2-locular, with ovules numerous in each locule on axile placentas; stigmas 2, exserted. Fruits capsular, subglobose to turbinate, septicidally dehiscent from apex, woody, with calyx limb persistent; seeds numerous, suborbicular, weakly flattened, small (0.3--1 mm), angled or with concentric marginal wing, wing entire to crenulate, seed surface foveolate.