A new dematiaceous hyphomycete, Elegantimyces sporidesmiopsis gen. et sp. nov., is described from decaying wood submerged in a stream in Hong Kong. It produces predominantly 3-septate, obclavate, versicoloured, solitary conidia at the apex of the sympodially regenerating conidiophores. The apical cell of the conidia is unique in becoming a sympodially proliferating conidiogenous cell producing an Idriella-like synanamorph. Conidial secession in this fungus is rhexolytic. Elegantimyces is compared with Sporidesmium bifasciatum, S. tropicale and S. urceolatum which also produce Idriella-like synanamorphs.