Infrageneric phylogeny of Chloantheae (Lamiaceae) based on chloroplast ndhF and nuclear ITS sequence data

Abstract

The tribe Chloantheae (Prostantheroideae, Lamiaceae) currently consists of over 100 species in nine genera, all of which are endemic to Australia. Generic delimitations were assessed using chloroplast 3′ndhF and nuclear ITS nucleotide sequence data for up to seventy species. Analyses of the two datasets, independently and in combination, used maximum parsimony and Bayesian phylogenetic inference methods. Topologies derived from each marker were broadly congruent, but better resolution and stronger branch support was achieved by combining the datasets. The monophyly of the Chloantheae was confirmed. Brachysola is sister to the rest of the tribe and Chloanthes, Cyanostegia and Dicrastylis (including Mallophora) are monophyletic. Although the species within Dicrastylis were only partially resolved, it appears likely that the current sectional classification of this genus will require revision. A clade containing Newcastelia, Physopsis and Lachnostachys (=Physopsideae) was recovered, but the topology indicates that the current generic circumscriptions need further investigation. A close relationship between Hemiphora elderi, Pityrodia bartlingii and P. uncinata was resolved and reflects their palynological and carpological similarities. The relationship between remaining species of Pityrodia was incompletely resolved.