Phylogeny of the "Ifloga clade" (Asteraceae, Gnaphalieae), a lineage occurring disjointly in the Northern and Southern Hemisphere, and inclusion of Trichogyne in synonymy with Ifloga

Ifloga and Trichogyne constitute a small but biologically interesting lineage within the tribe Gnaphalieae (Asteraceae).Species are distributed mainly in the semi-arid parts of southern Africa, but there is a disjunction to the Saharo-Sindian region where three species occur. Due partly to an unusual capitulum structure, the phylogenetic position of the group has been little understood. In addition, the monophyly of the genera has not been assessed using phylogenetic methods. A species-level phylogenetic hypothesis is presented, based on one nuclear and two chloroplast DNA regions, analysed with parsimony and Bayesian methods. Ifloga + Trichogyne constitute the "Ifloga clade" that forms one of the early-diverging lineages within Gnaphalieae.These lineages constitute a basal grade with many poorly supported nodes, precluding robust hypotheses of relationships amongst the lineages. A sister lineage to the Ifloga clade could thus not be identified, although it diverges amongst taxa formerly united in subtribe Relhaniinae. Although this subtribe is now known to be non-monophyletic, members of the Ifloga clade share with former members of Relhaniinae a previously overlooked set of leaf characters. The genus Trichogyne is monophyletic, but Ifloga is paraphyletic with respect to Trichogyne. To retain generic monophyly, all species are here transferred to the genus Ifloga.Although two of the Northern-Hemisphere species were not included in the analysis, morphological characters suggest that the three species from this region are monophyletic, in which case the Saharo-Sindian distribution is the result of a single dispersal northwards from Southern Africa. A new combination and an updated key to the species are presented.