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

Abstract

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