东亚-北美间断分布稀花薹草组Carex sect. Paniceae(莎草科)的系统分类研究

Cyperaceae, a monocot family in the order Poales, contains 106 genera and ca. 5400 species worldwide, with closest relatives, Juncaceae and Thurniaceae. With more than 2000 species, Carex L. is the largest genus in the family Cyperaceae. The genus has traditionally been divided into four subgenera: subg. Vigneastra (Tuck.) Kük., subg. Vignea (B. Beauv. ex Lestib.) Peterm., subg. Psyllophora (Degl.) Peterm., and subg. Carex. More recently, these subgenera are known to be largely polyphyletic or paraphyletic, with the notable exception of subg. Vignea. The genus Carex itself, however, is cosmopolitan and easily distinguished from the other genera of Cyperaceae based on the combination of unisexual flowers and achenes enveloped in perigynia..With a number of species and a large dispersal region, and limited specimens, the taxonomic revision and floristic studies on Carex are considered as one of the difficult problems in angiosperm. During the preparation of the regional florae, the investigation and taxonomy of Carex were fairly in-depth in the recent 40 years, but a lot of divergences and problems in species delimitation, generic subdivision, and geographical distribution etc. still need to be solved. All these indicate that the cognition of morphological characters and its systematic significance are far from a satisfactory status..Based upon field work, population sampling, specimen examination of the main herbaria both at home and abroad, this project will use statistical analysis and analyze the variation of the morphological characters, which are used to identify the species in Carex sect. Panicaeae. We will also evaluate the taxonomic significance/value of these characters, carry out phylogenetic analysis and DNA barcoding on Carex jackiana Complex and C. filipes Complex, and make a full-scale revision of Carex sect. Paniceae, as well as delimitate this section and similar ones. It can accelerate the taxonomic revision, systematics, origin, dispersal and the floristic studies of the whole genus Carex. The project will benefit for cultivating reserve talents of phytotaxonomy.

薹草属Carex（莎草科Cyperaceae）是被子植物的大属，其分类历来被视为是一大难题。近来薹草属的系统分类学研究取得了较大进展，但在种的划分、属内组的界定等方面仍存在问题和严重分歧，反映出以往对薹草属研究方法单一，对多学科综合评价和分析系统分类问题的认识不足。.本研究旨在前人研究的基础上，坚持以居群概念为指导，对东亚-北美间断分布的稀花薹草组Carex sect. Paniceae植物进行深入的野外调查和标本采集，国内外主要标本馆标本的全面查阅和观测，用统计学方法分析种间及种内居群间的形态变异，探讨和评价形态性状（包括宏观形态、叶表皮、果囊及小坚果的微形态）的变异式样及其系统分类学意义，对疑难种开展DNA barcoding研究，结合分子系统学研究结果，对本组进行界定及全面的世界性修订。本项目既可以为Carex系统分类研究提供借鉴，也可以培养植物经典分类和系统进化研究的后备人才。

薹草属稀花薹草组Carex sect. Paniceae是薹草属中种类较丰富的组之一，产于东亚和北美，少数种分布于欧洲，分类问题十分突出。本研究在标本查阅、野外采集、标本鉴定的基础上，对本组大部分种进行了小坚果和果囊扫描电镜观察、叶表皮和叶片解剖结构实验，分析和评价了这些微形态性状及宏观性状的分类学和系统学意义。依次作为证据，结合大量标本研究后，对世界范围内密花薹草组进行了组的界定和分类学修订，结果如下：（1）根据小坚果的形态和微形态显示组内稳定性，但在某些种间具有分类学价值；（2）果囊的形态和微形态在种内也较为稳定，东亚和北美的类群间无差异，对组内次级划分意义虽不明确，但作为区分近缘种或种下类群有一定的意义；（3）叶表皮特征在不同组间几无差异，可以作为区分某些种或种下类群的依据；（4）叶片解剖结构在对东亚和北美的种有价值，具有分类学意义；（5）对C. jackiana复合体和C. filipes复合体进行了DNA条形码的分析工作，可以为复合种的分类处理提供证据；（6）基因4个基因片段的系统发育关系分析显示采用广义稀花薹草组更为合适；（7）修订后承认了本组全世界共40种、3变种，提升新组合种级1个，将23个分类群名称处理为异名；（8）C. baimaensis、C. giraldiana、C. longerostrata等不属于稀花薹草组。