Phylogenetic relationships of two anomalous species of Pultenaea (Fabaceae: Mirbelieae), and description of a new genus

Abstract

The phylogeny of genera related to Pultenaea was investigated using three independent data sets: morphology and nucleotide sequences of non-coding DNA from the nucleus (ITS) and the chloroplast (trnL-F). Elucidating the relationships of two species anomalous in Pultenaea - P. neurocalyx and P. selaginoides - was the principal question. Despite some incongruence among the data sets, P. neurocalyx is unambiguously placed with Eutaxia, but its formal taxonomic placement - either as a species of Eutaxia or as a monotypic new genus - is left undecided pending a species-level analysis of that group. The precise phylogenetic position of P. selaginoides is not clear, due to incongruence between the ITS and trnL-F data sets. Its most likely relationship is with Almaleea, as indicated by both morphology (weakly) and trnL-F (strongly). To accommodate this species, a unispecific new genus, Stonesiella, is created, diagnosed by characters of the inflorescence and bracts, and the absence of all synapomorphies of the other Pultenaea-group genera. The appropriateness of recognising monotypic genera is discussed. Monophyly of Pultenaea s.str. (excluding P. selaginoides and P. neurocalyx) is supported equivocally.