Phylogenetic relationships of the whole Poaceae family inferred from the
sequence data of rDNA (ITS) support the hypothesis that the arundinoids are
monophyletic, not polyphyletic as previously proposed. The ITS sequence
phylogeny of 42 arundinoid species demonstrates an early divergence of the
Aristideae and three major groupings, corresponding loosely to the tribes
Aristideae, Arundineae and Danthonieae. The Arundineae are resolved into two
paraphyletic clades. In one clade, Arundo,
Monachather, and Dregeochloa are
the sister group to Amphipogon and
Diplopogon. In the other clade,
Phragmites, Molinia,
Gynerium, Thysanolaena,
Spartochloa, and Cyperochloa are
the sister group to Eriachne and
Micraira. Arundo is not closely
related to Phragmites. The Danthonieae clade, including
taxa from Africa, Australia, New Guinea, New Zealand, the South American
Cortaderia, and the North American
Danthonia, appears to be monophyletic. However, the
genus Merxmuellera is polyphyletic.