Molecular phylogeny of Anaphalis (Asteraceae, Gnaphalieae) with biogeographic implications in the Northern Hemisphere

Anaphalis is the largest Asian genus in the tribe Gnaphalieae (Asteraceae) and has its greatest species diversity in the eastern Himalayas. The nuclear internal and external transcribed spacers were sequenced for Anaphalis species, with an emphasis on the eastern Himalayan taxa to examine the monophyly and construct the phylogenetic relationships of and within the genus. The results suggest that all species of Anaphalis are nested with Helichrysum, showing a close relationship with a Mediterranean-Asian group of Helichrysum. Although the monophyly of Anaphalis is only weakly supported, two clades within the genus are well recognized, each consisting of two subgroups. The inferred phylogenetic relationships within Anaphalis correspond to the shape of leaf base, rather than the morphology of the capitula and phyllaries that are usually used for species delimitation and classification in the genus. All four subgroups of Anaphalis are common and diversified in the eastern Himalayas with multiple dispersals out of this region. The sole North American species of Anaphalis is best hypothesized to be the result of long-distance dispersal or overland migration via Bering land bridge from Asia. Our analyses suggest that the extant distribution of Anaphalis has most likely resulted one radiation into the eastern Himalayas followed by repeated independent dispersals and/or radiations mostly into eastern Asia but also into the western Himalayas, North America, and southeast Asia.