Disjunction is an important biogeographic pattern which used to be addressed using phylogenetic and historical biogeographic ***,there are extremely rare larger-scale, particularly inter-continental,phylogeographic in...
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Disjunction is an important biogeographic pattern which used to be addressed using phylogenetic and historical biogeographic ***,there are extremely rare larger-scale, particularly inter-continental,phylogeographic investigations on closely related *** diversification and evolution of the disjunct taxa after divergence have also scarcely been ***, we applied phylogenetic and phylogeographic analyses to understand the evolutionary history of a morphologically static group,Smilax hispida complex(including ***(华东菝葜) and S. scobinicaulis(短梗菝葜) in east Asia;*** in northwest America;*** in northeast America;*** and *** in central America),with a broad eastern Asian and North-Central American *** phylogeographic analyses,we sequenced two cpDNA fragments(trnL-trnF and ycf6-trnC spacers) and also nuclear(ITS) region in 539 individuals from 64 populations of sampled throughout the six species' *** present suite of molecular data strongly supports the monophyly of S. hispida complex and the first divergence between the intercontinental lineages as well as delineation of each of the six *** species complex most possibly originated in western North America and then dispersed into eastern Asia via the Bering land *** intracontinental divergence closely followed the intercontinental disjunction at 8 *** in Central America is the first diverged species in the American clade prior to *** in western North America at 5.1 *** divergence between S. hispida in eastern North America and *** in northern Mexico was estimated at 2.8 *** origin of temperate plants in Central America is more complex than what we have known *** earliest and latest diverged species in American clade,*** and ***,independently migrated into Central America in different times even up to 8.2 *** did occur between them during t
本文观察了中国伞形科所有山芹属共7种1变种的果实解剖学特征。该属的果实(分生果)横切面的解剖结构比较一致,在伞形科各属中也比较特殊,易于鉴别。其主要特征为角质层厚,外果皮细胞的外壁向外弯拱,常呈波浪形,中果皮无木化网纹细胞,薄壁细胞层数少,常收缩成一圈大的空腔,侧棱菲薄,除顶端外其余部位中空。这些独特的解剖学特征有力地支持了山芹属应当从当归属中独立成一属的处理。根据分生果横切面果体和侧棱的形状及外果皮细胞外壁弯拱程度,将山芹属果实解剖结构分为两种类型,为该属的分组处理提供了解剖学依据。同时,结合细胞学和孢粉学资料对该类型和种类的演化趋势以及与近缘属间的演化关系进行了简要的讨论。此外,高山全叶山芹Ostericum ***由于其果实解剖特征与原种山芹有较大差别,结合外部形态上的差异,认为其应提升成种,即高山山芹(新拟)***(Yuan etShah)*** et ***。
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