Phylogenetics and evolution of epacrids:: a molecular analysis using the plastid gene rbcL with a reappraisal of the position of Lebetanthus

An expanded rbcL sequence dataset has been assembled for all capsular-fruited genera and a majority of fleshy-fruited genera in Epacridaceae sensu Powell et al. (1996), including a new accession of the South American monotypic Lebetanthus Endl. Parsimony and maximum likelihood analyses strongly support an epacrid clade which includes both Lebetanthus and Prionotes R.Br. These two taxa are robustly grouped and placed sister to the rest of the family. Most of the remaining epacrids fall into several well-supported groups, some of which correspond to previously recognised infrafamilial taxa: the Cosmelia, Epacris, Richea and Styphelia groups. Needhamiella L.Watson and Oligarrhena R.Br. form a clade that is distant from the Styphelia group, to which they have traditionally been allied on the basis of their fleshy fruit and uniovulate locules. Archeria Hook.f., a small genus found in New Zealand and Tasmania, is distant from all of these well-supported groups, including its traditional ally, the Epacris group. Several novel generic relationships are evident on the rbcL tree. Epacris Cav. is paraphyletic; one of the included species clusters robustly with Budawangia Telford and Rupicola Maiden & E.Betche. Strong evidence is also advanced for the position of Pentachondra R.Br. as sister to the remainder of the Styphelia group. Beyond this, however, relationships within the Styphelia group are poorly supported. On the basis of these results, a new taxonomy of the epacrids, comprising seven tribes, is proposed. Six of these correspond to previously recognised taxa; one new tribe, Archerieae, is recognised. A key to the tribes is provided. Character evolution within the family is discussed and reinterpreted in the light of the rbcL tree.