rhododendron (rōˌdədĕnˈdrən) [key] [Gr., = rose tree], any plant of the genus Rhododendron, shrubs of the family Ericaceae (heath family) found chiefly in mountainous areas of the arctic and north temperate regions and also of the mountainous tropics. Encompassing more than 1,000 species, they are particularly abundant in Asia, whence many of the popular cultivated species and hybrids derive. They commonly have large, shining, leathery, evergreen, semievergreen, or deciduous leaves and clusters of large pink, white, or purplish flowers. Native American species include the great laurel, or rose bay ( R. maximum ), the common eastern species and the state flower of West Virginia; the mountain rose bay ( R. catawbiense ) of the southern mountains; and the western rhododendron ( R. californicum ), the state flower of Washington. The azalea and the rhodora are names used for similar shrubs of the same genus with more typically deciduous leaves. Rhododendrons are classified in the division Magnoliophyta, class Magnoliopsida, order Ericales, family Ericaceae.
See F. P. Lee, The Azalea Book (1965); C. L. Phillips, The Rothschild Rhododendrons (1967); J. Brown, Tales of the Rose Tree (2006).