MOLECULAR PHYLOGENY OF THE EDELWEISS (LEONTOPODIUM, ASTERACEAE – GNAPHALIEAE)

Abstract

Leontopodium is a genus of approximately 30 species with a conspicuous Asian–European disjunct distribution. In this study samples from the Himalayan/Tibetan centre of diversity of the genus, as well as from Europe, were analysed to infer a phylogeny of the genus using sequences of nuclear ribosomal (ITS and ETS) and plastid (matK and trnL/F) DNA. The Southeast Tibetan monotypic Sinoleontopodium [Leontopodium lingianum (Y.L.Chen) Dickoré, comb. nov.] falls into Leontopodium. Monophyly of Leontopodium, including Sinoleontopodium, is supported. Due to low rates of sequence divergence, intrageneric relationships in general are weakly supported, a pattern frequently observed in plant groups centred in the Tibetan Plateau. Three phylogenetic groups can be identified, however, and these are also supported by morphology. The low levels of nucleotide divergence suggest a young age for the group, which has been influenced by the turbulent geological history of the Tibetan Plateau. Leontopodium is a characteristic Sino-Himalayan element that appears to have found its way into the mountains of Europe in geologically recent times. The two European taxa, Leontopodium alpinum and L. nivale, form a genetically distinct group, which, considering the wide geographic disjunction, shows surprisingly little divergence from its Asian relatives.