Resurrection of the East Asian genusEremotropa(Monotropoideae, Ericaceae), based on molecular and morphological data

The monotypic genus Eremotropa Andres (Monotropoideae, Ericaceae) is endemic to central Yunnan. It was first described by Andres in 1953, and was subsequently treated as a synonym of Monotropastrum Andres (1987); however, the phylogenetic placement of this genus has not, to date, been investigated. In this study, phylogenetic analyses were undertaken using DNA sequences from the nuclear internal transcribed spacer from all species of Monotropoideae available in GenBank. Comparative morphological studies on Eremotropa, Monotropastrum, and Monotropa L. were also carried out. The molecular phylogenetic evidence suggests that Eremotropa is sister to a clade formed by Monotropa and the remaining species of Monotropastrum, thus rendering Monotropastrum not monophyletic. Morphologically, Eremotropa differs from Monotropastrum in plant color, inflorescence type, length of the style, and size of the baccate fruit. Consequently, molecular and morphological evidence supports the resurrection of Eremotropa, which contains only one species, E. sciaphila Andres, as distinct from Monotropastrum.