Evergreen or deciduous trees, shrubs, or prostrate shrublets, sometimes epiphytic, either scaly (lepidote rhododendrons) or lacking scales (elepidote rhododendrons). Lvs alternate, entire or rarely ± serrulate, petiolate. Fls mostly in terminal panicles, racemes or umbels, much less commonly axillary or solitary, pedicellate, with deciduous scales (perulae). Calyx 5-(10)-lobed, accrescent but sometimes reduced to a rim. Corolla 5-(10)-lobed, very variable in shape but generally campanulate, funnelform or broadly tubular, usually slightly zygomorphic. Stamens usually 5-10, sometimes more, commonly twice as many as corolla lobes, included or exserted; anthers with apical pores. Fr. a woody septicidal capsule, usually ovoid to oblong. Seeds numerous, minute.