(n) group of evergreen or deciduous shrubs formerly considered a separate genus; now included in the genus Rhododendron, Syn. subgenus Azaleastrum, Azaleastrum
n.; pl.Subgenera (Biol.) A subdivision of a genus, comprising one or more species which differ from other species of the genus in some important character or characters; as, the azaleas now constitute a subgenus of Rhododendron. [ 1913 Webster ]