A plastid tree can bring order to the chaotic generic taxonomy of Rytidosperma Steud. s.l. (Poaceae)

作者：Humphreys Aelys M^*; Pirie Michael D; Linder H Peter

来源：Molecular Phylogenetics and Evolution, 2010, 55(3): 911-928.

DOI：10.1016/j.ympev.2009.12.010

• Bootstrap support
• Chloroplast
• cpDNA
• Danthonioideae
• Generic delimitation
• Morphology
• Phylogeny
• Southern Hemisphere
• Wallaby grass

Rytidosperma s.l., wallaby grasses and allies, is in dire need of a single, unanimously accepted generic taxonomy. Motivated by the desire to establish a generic classification that complies with phylogeny, we investigated how much phylogenetic signal is contained within a plastid (cpDNA) tree, given that the nrDNA tree (ITS) was uninformative and that a phylogenetic hypothesis based on a single genome may not be reliable. We find that the plastid tree is significantly different from a morphological cladogram and show that this is the result of homoplasy in the morphological dataset. Treated individually, several morphological characters fit the plastid tree very well. Similarly, we find a good fit of the plastid tree with ecological and distribution characters and with biogeographical patterns in the Southern Hemisphere. We conclude that a significant level of the species phylogeny is resolved by the plastid tree and are confident it can form a sound basis for a reconsideration of generic limits. None of the currently recognised seven genera in the Rytidosperma clade is monophyletic. Therefore, we propose combining the segregate genera in Australasia within a broadly construed Rytidosperma, including all the species from Australia, New Guinea, New Zealand and South America.

• 出版日期2010-6