Rhododendron farrerae Tate ex Sweet (Ericaceae), a Reconfirmed Species in Taiwan

Rhododendron farrerae Tate ex Sweet was first recorded in Taiwan by Kawakami in 1910. Since then, this species
has been grouped with R. tashiroi Maxim. due to insufficient reports and specimens, and was eliminated from Flora of Taiwan in
1998. By examining all the specimens preserved in Taiwan herbaria and documents, we confirm that the native population of R.
farrerae is actually distributed in southern Taiwan, ranging from Peitawushan to Tajen Township, in the southern part of the Central Mountain Range. The diagnostic character distinguishing R. farrerae from R. tashiroi and R. mariesii Hemsl. & E. H. Wils. is that R. tashiroi and R. mariesii bear 2-3 flowers from each bud at anthesis; in contrast, R. farrerae bears only one flower during the flowering period. We provide in this paper a detailed taxonomic treatment, morphological description, distribution map, line
drawing, and a comparison table of these three species of Taiwan, together with photographs.