Phylogenetic relationships of Xerochrysum, Coronidium and Helichrysum leucopsideum reveal a new genus, Leucozoma (Asteraceae: Gnaphalieae)

Abstract

We gathered morphological data and genome‐wide single nucleotide polymorphisms to infer the evolutionary relationships of Xerochrysum, Coronidium, and Helichrysum leucopsideum, and to test the circumscription of the genera. SVDquartets species tree topology resolved relationships between the genera and within subsets of the Xerochrysum data. Results corroborated previous conclusions that Coronidium is non‐monophyletic as presently circumscribed and forms, in addition to the more distantly related Coronidium scorpioides group, three morphologically distinct clades. SVDquartets returned two clades in Xerochrysum, though species‐level relationships were unclear. Bayesian coalescent analysis using SNAPP produced tree topologies for the three clades of Coronidium with most species‐level relationships well resolved. The new genus Leucozoma is described for seven taxa previously included in Coronidium. A revised description of Coronidium and images of phyllary and fruit diagnostic morphological characters are provided.