Wen J, Shi S, Jansen R, Zimmer E
Am J Bot. 1998 Jun;85(6):866.
Aralia sect. Aralia (Araliaceae) consists of approximately eight species disjunctly distributed in Asia and North America. Phylogenetic and biogeographic analyses were conducted using sequences of the internal transcribed spacer regions of the nuclear ribosomal DNA. Aralia racemosa from eastern North America was sister to A. californica from western North America. Aralia cordata from eastern Asia did not form a species-pair relationship with the eastern North American A. racemosa. The two subspecies of A. racemosa formed a monophyletic group. Biogeographic analyses showed a close area relationship between eastern North America and western North America. The Himalayas were cladistically basal and eastern Asia was placed between the Himalayas and North America. The biogeographic analysis supported the origin of the eastern Asian and eastern North American disjunct pattern in Aralia sect. Aralia via the Bering land bridges. Comparisons with results of phylogenetic analyses of other genera suggested that (1) the floristic connection between eastern North America and western North America may be stronger than previously thought; and (2) the biogeographic patterns in the Northern Hemisphere are complex. Furthermore, a lack of correlation between sequence divergence values and phylogenetic positions was observed, suggesting the importance of a phylogenetic framework in biogeographic analyses.
楤木组（五加科）约由8个物种组成，间断分布于亚洲和北美洲。利用核糖体DNA的内转录间隔区序列进行了系统发育和生物地理学分析。来自北美洲东部的总序楤木是来自北美洲西部的加州楤木的姐妹种。来自东亚的轮叶楤木与北美洲东部的总序楤木没有形成种对关系。总序楤木的两个亚种形成了一个单系类群。生物地理学分析表明北美洲东部和北美洲西部之间存在密切的区域关系。喜马拉雅地区在分支上处于基部位置，东亚位于喜马拉雅地区和北美洲之间。生物地理学分析支持了楤木组中东亚和北美洲东部间断分布模式通过白令陆桥起源的观点。与其他属的系统发育分析结果比较表明：（1）北美洲东部和北美洲西部之间的植物区系联系可能比以前认为的更强；（2）北半球的生物地理模式很复杂。此外，还观察到序列分歧值与系统发育位置之间缺乏相关性，这表明系统发育框架在生物地理学分析中的重要性。
