Institute of Systematic Botany, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
Mol Phylogenet Evol. 2010 Jun;55(3):911-28. doi: 10.1016/j.ympev.2009.12.010. Epub 2009 Dec 21.
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.
Rytidosperma s.l.(袋鼠草属及近缘植物)迫切需要一个单一的、被普遍接受的通用分类单元。受建立一个符合系统发育的分类单元的愿望驱使,我们研究了叶绿体(cpDNA)树中包含了多少系统发育信号,因为核核糖体 DNA 树(ITS)没有提供信息,而且基于单个基因组的系统发育假说可能不可靠。我们发现叶绿体树与形态系统发育树有显著差异,表明这是形态数据集出现同形现象的结果。个别处理时,几个形态特征与叶绿体树非常吻合。同样,我们发现叶绿体树与生态和分布特征以及南半球的生物地理模式也有很好的吻合。我们得出结论,叶绿体树解析了物种系统发育的显著水平,我们有信心它可以为重新考虑通用限制提供一个合理的基础。目前在 Rytidosperma 分支中识别的七个属都不是单系的。因此,我们建议将澳大利亚的分离属合并到广义的 Rytidosperma 中,包括来自澳大利亚、新几内亚、新西兰和南美洲的所有物种。