Generic and infrageneric limits of Phebalium and its allies (Rutaceae: Zanthoxyloideae)

Abstract

We present a five-locus 129-species phylogeny of Rutaceae from subfamily Zanthoxyloideae, with 193 ingroup samples representing 128 species from all 18 genera in the Eriostemon Group and focus on generic and infrageneric limits in Phebalium and its allies. Maximum parsimony and Bayesian inference analyses were performed using three plastid markers (psbA–trnH, trnL–trnF, rbcL) and two nuclear ribosomal markers (ITS, ETS). Asterolasia, Correa, Diplolaena, Eriostemon, Leionema, Nematolepis and Phebalium are each shown to be monophyletic, reaffirming the results of previous authors. The paraphyly of Rhadinothamnus with respect to Chorilaena is addressed by transferring all taxa of Rhadinothamnus into an expanded Chorilaena and a key to species presented. Microcybe is reduced to synonymy under Phebalium and recognised at a sectional level, with the distinctiveness of M. ambigua recognised by erecting a new monotypic section to accommodate it. The denser sampling of the Eriostemon Group in this study has not improved resolution among genera; there is little support for most relationships among genera, a finding similar to that of previous authors. New sectional classifications with keys are presented for Asterolasia, Leionema, Nematolepis and Phebalium.