Sequences of the grass-specific insert in the chloroplast rpoC2 gene elucidate generic relationships of the Arundinoideae (Poaceae)

Phylogenetic relationships of the genera in the subfamily Arundinoideae are examined using sequence data from a variable insert in the plastid rpoC2 gene. Results suggest that the Arundinoideae comprise several Lineages as well as misplaced taxa. Two of the larger lineages correspond to the tribes Arundineae and Danthonieae. The Arundineae as delimited here are not clearly defined, and this analysis does not provide much insight into the composition of the lineage. In contrast the Danthonieae are clearly defined by molecular, as well as morphological, data. The results indicate that several groups may be recognised within the Danthonieae: a group centred on the African genus Pentaschistis, a widespread group including Rytidosperma, Tribolium, and several other austral genera, as well as a group including Danthonia s.s. and two small Australian genera. In addition, there are some indications that both Merxmuellera and Cortaderia may not be monophyletic.