Data from: New taxa of Rhododendron tschonoskii alliance (Ericaceae) from East Asia

Three new taxa, Rhododendron sohayakiense Y. Watan. & T. Yukawa
(Ericaceae), and its two varieties, var. kiusianum Y. Watan., T. Yukawa
& T. Minamitani and var. koreanum Y. Watan. & T. Yukawa
are described and illustrated from Japan and South Korea. They can be
distinguished each other and from the other members of the R. tschonoskii
alliance, i.e. R. tschonoskii, R. tetramerum, R. trinerve and R.
tsusiophyllum, by the combination of leaf size, leaf morphologies
including lateral nerves on abaxial leaf surface, corolla morphologies
including number of corolla lobes, style length and anther form.
Phylogenetic inferences based on chloroplast DNA and genome-wide sequences
revealed that each of the three new taxa is monophyletic and they further
form a clade. Distributions of the three taxa are also clearly separated
each other and also from the other members of the R. tschonoskii alliance.