世界薹草属密花薹草组（莎草科）的分类修订

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 (Reznicek, 1990), 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 (Govaerts & al., 2007; Dai & al., 2010). More recently, these subgenera are known to be largely polyphyletic or paraphyletic, with the notable exception of subg. Vignea (Waterway & Starr, 2007). 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 (Nelmes, 1951). 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 awaiting solved. All these indicates 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. Confertiflorae (s. l.). We will also evaluate the taxonomic significance/value of these characters, and make a full-scale revision of Carex sect. Confertiflorae s. l., 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是被子植物的大属，全世界约2000种，因为种类多、分布广，该属分类历来被视为是一大难题。薹草属积累的标本少，分类学、系统学和区系地理学研究的材料有限。虽然近40年来，随着植物志编撰和深入调查采集，薹草属的分类研究也取得了较大进展，但在种的划分、属下次级系统划分等方面都存在问题和严重分歧，也反映出以往对形态性状的系统分类学意义认识不足。本研究在前人研究基础上，始终坚持以居群概念为研究指导，对种类较多、分类问题突出的密花薹草组Carex sect. Confertiflorae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，探讨形态性状变异式样及其系统分类学意义，结合疑难种DNA条形码研究,对本组进行世界性修订。以此为薹草属系统分类研究提供借鉴，也可为本属区系地理研究积累更多标本，同时可培养植物分类学研究生2-3名

薹草属广义密花薹草组Carex sect. Confertiflorae s.l.是薹草属中种类较丰富的组之一，主产东亚，少数种分布于东南亚至澳大利亚，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，广义密花薹草组种类可分为5个类型，与传统的分组不一致，但具有分类学价值；（2）果囊的形态和微形态在种内也较为稳定，分为5个类型，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）叶表皮特征在近缘种和种下等级之间都存在显著区别，可以作为广义密花薹草组内区分种或种下类群的依据；（4）叶片解剖结构在对划分狭义密花薹草组及柔果薹草组有价值，同时也有分类学价值；（5）对日本薹草复合体和皱果薹草复合体进行了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广义密花薹草组可以分为狭义密花薹草组和柔果薹草组，（7）修订后承认了本组全世界共26种、7亚种，除了前期发表的2个新种外，还发现了新种1个：斜果薹草Carex obliquicarpa、细喙薹草C. tenuirostrata、洪林薹草C. honglinii，组合种1个、新组合亚种6个，新亚种1个C. retrofracta subsp. glabrifolia，将35个分类群名称处理为异名；（8）Carex harry-smithii、C. phaenocarpa、C. gauciformis不属于密花薹草组。