Molecular phylogeny of the ‘Cape snow’ genus Syncarpha (Asteraceae: Gnaphalieae) reveals a need for generic re-delimitation

Abstract

A phylogenetic hypothesis is presented for the charismatic but taxonomically poorly-known Cape daisy genus Syncarpha, based on near-complete ingroup sampling and good coverage of outgroup taxa. A combination of nuclear ribosomal and chloroplast spacer DNA sequence data gives a well-resolved phyogenetic hypothesis, the robustness of which is assessed via both parsimony bootstrap and Bayesian posterior probabilities based on the uncorrelated lognormal relaxed clock model. Syncarpha species fall into two well-supported and distantly-related clades that last shared a common ancestor in the mid-Miocene. The larger Syncarpha 1 grouping contains the type species and corresponds to African ‘Helipterum’; this clade is sister to Edmondia and belongs in a larger clade which also includes the Australian Gnaphalieae. The Syncarpha 2 clade contains the taxa associated with Syncarpha paniculata (formerly Helichrysum paniculatum) and is more closely related to Plecostachys and some species of Gnaphalium. Formal assessment of monophyly lays the groundwork for future revisionary taxonomic work.