Molecular phylogeny of Ericameria (Asteraceae, Astereae) based on nucler ribosomal 3′ ETS and ITS sequence data

Phylogenetic relationships and composition of Ericameria were investigated by parsimony, maximum likelihood and Bayesian analyses of ITS and 3' ETS sequences for 50 taxa including all known species in Ericameria and several related taxa. The independent analyses of the data sets led to highly congruent, though not identical, results. Analyses of the combined sequence data generally improved resolution and clade support. Ericameria, Pentachaeta, Rigiopappus and Tracyina are resolved in a monophyletic group distinct from Chrysothamnus, Xylothamia, and representatives of the Solidago lineage. The expanded circumscription of Ericameria to include sections Asiris, Macronema and Stenotopsis, and species transferred from Chrysothamnus including E. albida, is supported. Within Ericameria the alignment of species into sections is not in total agreement with previously proposed relationships. Also, the molecular data do not support the treatment of section Stenotopsis as distinct from section Ericameria.