Phylogenetic studies in Gnaphalieae (Compositae): The genera Phagnalon Cass. and Aliella Qaiser & Lack

Abstract

The precise generic delimitation of Aliella and Phagnalon, and their closest relatives within the Gnaphalieae are discussed in this review. Among the main results obtained, we have found that the genera Aliella and Phagnalon are nested within the “Relhania clade” and Anisothrix, Athrixia and Pentatrichia are their closest relatives. Macowania is also part of the “Relhania clade”, whereas the subtribal affinities of Philyrophyllum lie within the “crown radiation clade”. The monophyly of Aliella and Phagnalon is not supported statistically. In addition, Aliella appears to be paraphylethic in most of the analyses performed. The resulting phylogeny suggests an African origin for the ancestor of Aliella and Phagnalon and identifies three main clades within Phagnalon that constitute the following natural groups on a geographic basis: (1) the Irano-Turanian clade; (2) the Mediterranean-Macaronesian clade; and (3) the Yemen-Ethiopian clade. Some endemics to Yemen and Ethiopia appeared merged in the Mediterranean- Macaronesian clade, providing new evidence of the phytogeographical links between Macaronesia, Eastern Africa and Southern Arabia. Incongruities between the chloroplast and nuclear molecular data and the lack of resolution in some clades may indicate that hybridization could have played an important role in the evolution and diversification of both Phagnalon and Aliella.