A molecular phylogeny of Raddia and its allies within the tribe Olyreae (Poaceae, Bambusoideae) based on noncoding plastid and nuclear spacers

- We infer relationships of the main lineages of Olyreae using a combined analysis of ITS and trnD-trnT sequence data.
- Within Olyrinae Raddia forms a strongly supported clade in the combined and individual analyses.
- Combined analysis supported Sucrea as sister to Raddia.
- Both individual and combined analysis confirmed Strephium as congeneric with Raddia.
- Combined datasets allowed us to outline some relationships within this group.

The plastid spacer trnD-trnT and the nuclear ribosomal internal transcribed spacer (ITS) were sequenced for 37 samples of herbaceous bamboos (Poaceae: Olyreae), including all Raddia species and allied genera, as well as two members of the woody bamboos (tribes Bambuseae and Arundinarieae), in order to examine their relationships. The sequences were analyzed using maximum parsimony and Bayesian inference. Both the individual and combined analyses of ITS and trnD-trnT supported Olyreae as a monophyletic group. All species of Raddia also formed a well-supported monophyletic group, and combined datasets allowed us to outline some relationships within this group. Individual analyses indicated incongruence regarding the sister group of Raddia, with ITS data weakly indicating Raddiella malmeana whereas trnD-trnT data supported Sucrea maculata in this position. However, the combined analysis supported Sucrea as sister to Raddia, although the monophyly of Sucrea is not well supported. Parodiolyra is paraphyletic to Raddiella in all analyses; Olyra is also paraphyletic, with species of Lithachne, Arberella and Cryptochloa nested within it. Eremitis and Pariana appeared as an isolated clade within Olyreae, and the position of the New Guinean Buergersiochloa remains uncertain within this tribe.