Diapensia L. is the second largest genus of Diapensiaceae. The taxonomic treatment within Diapensia and relationships within Diapensiaceae have been disputed. Chloroplast genome sequence data have proved to be useful for plant phylogenetic analyses and species delimitation. In this study, we de novo sequenced and assembled 22 chloroplast genomes of 15 species of Diapensiaceae, including all recognized species of Diapensia with multiple samples. A super‐matrix containing a total of 107 genes and 18 taxa was constructed for phylogenetic analyses to resolve phylogenetic relationships among genera of the family and within Diapensia. The resulting phylogenetic tree showed the following strongly supported relationships: (Galax, (Pyxidanthera, (Berneuxia, ((Schizocodon, Diapensia), and Shortia s.s.)))). The dated phylogeny and reconstructed lineage‐through‐time plot for the family indicated rapid diversification in the Neogene and an acceleration of diversification rate after c. 8 Ma. Biogeographic analysis suggested that Diapensia originated in the Northeast Asian mountains approximately 6.06 Ma, followed by northward dispersal to the Arctic and southwestward dispersal to the Himalaya–Hengduan Mountains. Phylogenetic relationships within Diapensia were well resolved. Based on the phylogenetic results, we proposed to reinstate the species status of Diapensia bulleyana Forrest ex Diels, and raised D. purpurea f. albida to the species rank (D. albida [W. E. Evans] J. F. Ye comb. & stat. nov.). The distribution ranges of all species delineated based on the phylogenetic results were revised accordingly based on specimen occurrences. Our study adds new examples for the power of plastid genome data for resolving phylogenetic relationships and clarifying taxonomic disputes among closely related species.

中文翻译：

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基于叶绿体基因组数据的 Diapensia (Diapensiaceae) 分类学和生物地理学

Diapensia L. 是 Diapensiaceae 的第二大属。Diapensia 内的分类处理和 Diapensiaceae 内的关系一直存在争议。叶绿体基因组序列数据已被证明可用于植物系统发育分析和物种定界。在这项研究中，我们从头测序并组装了 15 种水草科植物的 22 个叶绿体基因组，包括所有已识别的水草科物种和多个样本。构建了一个包含总共 107 个基因和 18 个分类群的超级矩阵，用于系统发育分析，以解决科属之间和 Diapensia 内部的系统发育关系。由此产生的系统发育树显示出以下强烈支持的关系：（Galax，（Pyxidanthera，（Berneuxia，（（Schizocodon，Diapensia）和Shortia ss））））。该家族的过时系统发育和重建的谱系-时间图表明新近纪的快速多样化和 c. 之后的多样化速度加快。8 马。生物地理学分析表明，Diapensia 起源于大约 6.06 Ma 的东北亚山脉，随后向北扩散到北极，向西南扩散到喜马拉雅山脉-横断山脉。Diapensia 内的系统发育关系得到了很好的解决。根据系统发育结果，我们建议恢复 Diapensia bulleyana Forrest ex Diels 的物种地位，并提高了 D. purpurea f。albida 到物种等级 (D. albida [WE Evans] JF Ye 梳子。& stat. nov.)。根据系统发育结果划定的所有物种的分布范围根据标本发生情况进行相应修订。