De Smet Yannick, De Clerck Olivier, Uemachi Tatsuya, Granados Mendoza Carolina, Wanke Stefan, Goetghebeur Paul, Samain Marie-Stéphanie
Ghent University, Department of Biology, Research Group Spermatophytes, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.
Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Krijgslaan 281 (S8), 9000 Gent, Belgium.
Mol Phylogenet Evol. 2017 Sep;114:415-425. doi: 10.1016/j.ympev.2017.05.021. Epub 2017 Jun 9.
The number of species recognized in section Asperae of the flowering plant genus Hydrangea differs widely between subsequent revisions. This variation is largely centered around the H. aspera species complex, with numbers of recognized species varying from one to nearly a dozen. Despite indications of molecular variation in this complex, no sequence-based species delimitation methods have been employed to evaluate the primarily morphology-based species boundaries. In the present study, a multi-locus coalescent-based approach to species delimitation is employed in order to identify separate evolutionary lines within H. sect. Asperae, using four chloroplast and four nuclear molecular markers. Eight lineages were recovered within the focal group, of which five correspond with named morphotypes. The other three lineages illustrate types of conflict between molecular species delimitation and traditional morphology-based taxonomy. One molecular lineage comprises two named morphotypes, which possibly diverged recently enough to not have developed sufficient molecular divergence. A second conflict is found in H. strigosa. This morphotype is recovered as a separate lineage when occurring in geographic isolation, but when occurring in sympatry with two other morphotypes (H. aspera and H. robusta), the coalescent species delimitation lumps these taxa into a single putative species.
绣球花属开花植物糙叶组中所认可的物种数量在后续修订中差异很大。这种差异主要集中在糙叶绣球物种复合体上，认可的物种数量从1种到近12种不等。尽管该复合体存在分子变异的迹象，但尚未采用基于序列的物种界定方法来评估主要基于形态学的物种界限。在本研究中，采用了基于多位点溯祖的物种界定方法，以便利用四个叶绿体和四个核分子标记来识别糙叶组内不同的进化谱系。在重点研究的类群中发现了八个谱系，其中五个与已命名的形态型相对应。另外三个谱系说明了分子物种界定与传统形态学分类法之间的冲突类型。一个分子谱系包含两个已命名的形态型，它们可能是最近才分化的，尚未产生足够的分子差异。在糙叶绣球中发现了第二个冲突情况。当该形态型在地理隔离状态下出现时，它被识别为一个单独的谱系，但当它与另外两个形态型（糙叶绣球和粗壮绣球）同域出现时，溯祖物种界定将这些分类群归为一个假定的物种。
