Revisiting of Carex sect. Confertiflorae s.l. (Cyperaceae): new data from molecular and morphological evidence and first insights on Carex biogeography in East Asia

Carex sect. Confertiflorae s.l., contains ca. 40 species and diverse in E Asia. It has one of the most unstable delimitations in the literature, and the section was proposed to split into two sections up to five different ones. Recent phylogenetic reconstructions showed Confertiflorae s.l. not to be monophyletic. In this study we investigate the phylogenetic structure, morphological affinities, and biogeographic history of sect. Confertiflorae s.l. We performed a taxon-based approach to explore the morphological affinities of the species considered in sect. Confertiflorae. We studied macromorphological observations and micromorphology of the nutlets using SEM, and used five molecular markers to reconstruct the phylogeny. The placement of all the species on a previously published megaphylogeny was tested in a preliminary exploration using a scaffolding approach. Then a core of species was selected to run the main analyses. The phylogenetic analyses confirmed the polyphyly of sect. Confer..., ,密花薹草组广义组（Carex sect. Confertiflorae s.l.）包含约40个物种，在东亚地区分布广泛且类群多样。该类群是分类学文献中界定最为不稳定的组之一，曾有多项研究提出将其划分为2个乃至最多5个独立的组。近期的系统发育重建研究显示，广义密花薹草组并非单系群。本研究针对广义密花薹草组的系统发育结构、形态亲缘关系与生物地理历史展开探究。本研究采用基于类群的研究方法，对该组涵盖物种的形态亲缘关系进行探索；通过扫描电子显微镜（Scanning Electron Microscope，SEM）开展小坚果的宏观形态观察与微观形态分析，并选取5个分子标记以重建系统发育关系。在初步探索环节，我们采用支架法检验了所有物种在已发表的大型系统发育树中的系统位置；随后选取核心类群开展核心分析。系统发育分析证实了密花薹草组的多系起源。