Paraphyly in Tribe Onagreae: Insights into Phylogenetic Relationships of Onagraceae Based on Nuclear and Chloroplast Sequence Data

Abstract

Onagraceae are a family of 17 genera in seven tribes, with the majority of species in tribes Onagreae and Epilobieae. Despite the species-richness of these two tribes, to date no phylogenetic study has been done with sufe cient taxon sampling to examine relationships between and within these tribes. In this study, we used DNA sequence data from one nuclear region (ITS) and two chloroplast regions ( trnL-trnF and rps16) to infer phylogenetic relationships among93taxa across thefamily, withconcentratedsamplinginthelargetribeOnagreae.Results stronglysuggestthattribeGongylocarpeae is sister to tribes Epilobieae 1 Onagreae, both of which are monophyletic. Within Onagreae, Camissonia seems to be broadly paraphyletic, and Oenothera is also paraphyletic. In Oenothera there appear to be two lineages, one of which has Gaura 1 Stenosiphon nested within it. At the base of the Onagraceae phylogeny, we have clarie ed previous confusion regarding cone icting placements of Hauya and Lopezia based on nuclear versus chloroplast data. Results of theseanalysesaresupported by morphology and suggest the need for new taxonomic delimitations, which are forthcoming.