The genus Rhododendron L., one of the largest and diverse genera of Ericaceae (Ericoideae,
Rhodoreae), comprises over 1000 species (Chamberlain et al., 1996). The centre of diversity of the genus is in the Himalaya, but Rhododendron sect. Vireya (Blume) Copel. f. is also diverse in Malesia (Sleumer, 1966)