柴胡属（Bupleurum L.）隶属于伞形科芹亚科柴胡族，全世界约195种，广泛分布于欧亚大陆和北非。我国是柴胡属重要的多样性中心之一。该属植物因其叶全缘、叶脉多条近平行、具明显的总苞片和小总苞片而易于与其他属识别。另外，柴胡属内多种植物为有名中药材，具有重要的经济价值。对物种的准确识别和鉴定是生物资源利用的重要前提，但柴胡属植物形态变异幅度广，尤其是对物种鉴定起重要作用的叶形和小总苞片变异式样不清，再加上其染色体基数和倍性的多样化，物种间的界限模糊。其次，现阶段使用核糖体和叶绿体基因片段构建的中国柴胡属系统发育树的分辨率低，类群间的亲缘关系也难以得到解析，无法为属下分类提供清晰框架。

本研究在系统整理文献的基础上，查阅了国内外28个标本馆的柴胡属馆藏标本及数字化照片8000余份。在新疆、青海、甘肃、宁夏、陕西、内蒙古、山西、河北等地进行了实地野外考察，共采集柴胡属202个居群，2000余份标本。在形态学方面，通过对标本照片测量形态性状，并进行数量分类学研究，并对果实进行了横切解剖，观察油管特征；在细胞学方面，基于野外采集后同质种植柴胡属12个类群进行染色体压片实验，观察染色体数目和倍性；在系统发育分析方面，基于二代测序数据，组装了叶绿体基因组、核糖体DNA和被子植物353核基因，并构建了中国柴胡属的系统发育树；综合以上研究，完成了对中国北方地区柴胡属的分类修订。本研究的主要结论如下：

（1）根据叶绿体基因组、核糖体DNA和被子植物353核基因构建的系统发育树结果，将中国的柴胡属分为两个组：柴胡组（sect. Bupleurum）和显脉组（sect. Nervosa Gren. & Godr.）。柴胡组为中国喜马拉雅支系，染色体基数为8，均为二倍体；显脉组为西伯利亚支系，染色体基数为4、6、7、8、13，倍性包括了二倍体、四倍体和八倍体，这两支在我国西南横断山区有交汇。依据被子植物353核基因多物种溯组构建的系统树可进一步将西伯利亚支系划分5个次级分支，且每个分支可与地理分布和染色体基数相匹配。另外，不同数据重建的系统树之间还存在比较严重的冲突，基于叶绿体基因组重建的系统树，各物种按照区域聚为不同分支，推测可能存在叶绿体的同域共享或捕获事件。

（2）对黑柴胡（B. smithii H. Wolff）与其近缘的小叶黑柴胡（B. smithii var. parvifolium R. H. Shan & Yin Li）、耳叶黑柴胡（B. smithii var. auriculatum R. H. Shan & Yin Li）、黄花鸭跖柴胡（B. commelynoideum var. flaviflorum R. H. Shan & Yin Li）、采自交城的居群和采自历山的居群等类群的形态变异研究发现，鉴定性状主要是叶形和小总苞片等性状，尽管这些性状在种内变化比较大，但在种间存在明显的间断性，仍是物种划分主要形态证据。小叶黑柴胡与黑柴胡原变种在形态上有一定的相似性，但细胞学、分子系统学和生物地理证据都支持它们不是变种等级的区别，支持黄花鸭跖柴胡处理为小叶黑柴胡的异名。

（3）确认东亚三岛柴胡复合群应包含9个中国分布的类群，这些类群在形态上叶均为披针形或狭披针形，小总苞片5数。大部分类群在系统发育树中都具有稳定的系统学位置，但该复合群并不为单系类群。而且北柴胡（B. chinense DC.）与其近缘的青海柴胡（B. qinghaiense Yin Li & J. X. Guo）、马尔康柴胡（B. malconense R. H. Shan & Yin Li）、空心柴胡（B. franchetii (H. Boissieu) X. J. He & C. B. Wang）等类群表现出了模糊的种间界限，在不同数据集重建的系统发育树中均相互冲突。形态和系统学结果支持用B. stenophyllum (Nakai) Kitag.而不是B. falcatum L.来指代东亚2n =26的实体，未发现该类群与其他物种之间存在杂交和渐渗等情况。对三岛柴胡复合群内各类群进行孢粉学观察，发现同一物种内花粉形态存在异质性。

（4）完成了对中国北方地区柴胡属的分类修订和处理，确认我国北方地区柴胡属有26种5变种。发现了1个新变种：交城黑柴胡B. smithii var. jiaochengense Q. R. Liu & L. H. Wang。提出了2个新组合，将小叶黑柴胡（B. smithii var. parvifolium R. H. Shan & Yin Li）从黑柴胡（B. smithii H. Wolff）的变种处理为单独的种（B. parvifolium (R. H. Shan & Yin Li) Q. R. Liu & L. H. Wang）；将雾灵柴胡（B. sibiricum var. jeholense (Nakai) Chu ex R. H. Shan & Yin Li）从兴安柴胡（B. sibiricum Vest ex Roem. & Schult.）的变种处理为北柴胡（B. chinense DC.）的变种（B. chinense var. jeholense (Nakai) Q. R. Liu & L. H. Wang）。提出了2个新异名，将黄花鸭跖柴胡（B. commelynoideum var. flaviflorum R. H. Shan & Yin Li）处理为小叶黑柴胡（B. parvifolium (R. H. Shan & Yin Li) Q. R. Liu & L. H. Wang）的异名；将甘肃柴胡（B. gansuense S. L. Pan & P. S. Hsu）处理为马尔康柴胡（B. malconense R. H. Shan & Yin Li）的异名。支持将短苞金黄柴胡（B. aureum Fisch.ex Hoffm. var. breviinvolucratum (Trautv. ex H. Wolff) R. H. Shan & Yin Li）归并入原变种金黄柴胡（B. aureum Fisch ex. Hoffm.）。确认B. stenophyllum (Nakai) Kitag.在我国有分布；确认我国记载的三辐柴胡（B. triradiatum Adams ex Hoffm.）的实体均为密花柴胡（B. densiflorum Rupr.）或紫花鸭跖柴胡（B. commelynoideum H. Boissieu）的错误鉴定，该种在我国没有分布。

The genus Bupleurum L. (Apiaceae, Tribe Bupleureae), which consists of about 195 species worldwide, is mainly distributed across Eurasia and North Africa. China is one of it’s significant diversity centers. The genus is easily recognizable from other genera by its entire leaves, numerous nearly parallel veins, and distinct involucral bracts and bracteoles. Additionally, several Bupleurum species are well-known as traditional Chinese medicinal herbs with significant economic value. Accurate species identification and authentication are crucial needed for the utilization of biological resources. However, there is a wide range of morphological variation within the genus, especially in leaf shape and involucels, which are crucial for species identification, and a range of variable. Moreover, the diversity in chromosome base numbers and ploidy levels. Furthermore, the current phylogenetic relationships of the Chinese Bupleurum constructed using ITS and chloroplast DNA sequences, have low resolution, thus making it difficult to resolve inter-species relationships and provide a clear framework for taxonomy.

Based on literature examination, the author examined more than 8000 specimens from 28 herbaria all over the world. Field surveys were conducted in Gansu, Hebei, Heilongjiang, Inner Mongolia, Ningxia, Qinghai, Shaanxi, Shanxi, and Xinjiang, more than 2000 specimens including from 202 populations have been collected. Morphologically, trait measurements were carried out using multiple field population specimens and digital photos, followed by a quantitative taxonomic method. Additionally, the cross-sectional anatomy of the fruits was examined to observe the oil tube characteristics. Chromosome number of 12 taxa that was counted from cultivated plants in greenhouse. In terms of phylogenetic analysis, based on the second-generation sequencing data, the chloroplast genome, ribosomal DNA and angiosperm 353 nuclear genes were assembled, to construct the phylogenetic tree of the Chinese Bupleurum. The comprehensive study in morphology, cytology, and molecular systematics led to the taxonomic revision of the Bupleurum genus in northern China. The main conclusions are summarized as follows:

1) The molecular phylogenetic studies based on cpDNA, nrDNA and angiosperm 353 nuclear genes all resolved, that the Chinese Bupleurum is divided into two sections: sect. Bupleurum and sect. Nervosa Gren. & Godr. Sect. Bupleurum is a Sino-Himalayan clade, with chromosome base number of eight, all of which are diploid; sect. Nervosa is a Siberian clade, with chromosome base numbers of 4, 6, 7, 8, 10 and 13, including diploid, tetraploid, and octaploid. These two clades is intersect in Southwestern China. The multi-species phylogenetic tree based on angiosperm 353 nuclear genes, resolved that the Siberian clade can be further divide into five sub-clades. And these clades could correspond to the geographical distribution and chromosome bases. In addition, there is a relatively serious conflict between the phylogenetic trees reconstructed from different data. The phylogenetic tree, reconstructed based on the cpDNA, showed that the species are clustered into different branches according to the region, suggesting potential sympatric sharing or chloroplast capture.

2) In order to study the morphological variation of B. smithii H. Wolff and its closely related taxa, including B. smithii var. parvifolium R. H. Shan & Yin Li, B. smithii var. auriculatum R. H. Shan & Yin Li, and B. commelynoideum var. flaviflorum R. H. Shan & Yin Li, populations samples were collected from Jiaocheng and Lishan of Shanxi province. Although the variation of these traits was relatively large within the species, the statistical results showed a clear discontinuity between different species by morphological characters. Bupleurum commelynoideum var. flaviflorum and B. smithii var. parvifolium are the same taxon.

3) The B. falcatum complex contains nine Chinese taxa. Leaves of these taxa are all lanceolate or narrowly lanceolate and bracteoles 5. Most of them have stable phylogenetic positions in the phylogenetic tree, but the B. falcatum complex is not monophyletic. B. chinense DC. and its close relatives, such as B. qinghaiense Yin Li & J. X. Guo, B. malconense R. H. Shan & Yin Li and B. franchetii (H. Boissieu) X. J. He & C. B. Wang, exhibit blurred interspecific boundaries. All these species are diploid, with a chromosome base number six, and molecular systematics evidence does not distinguish from them. Morphological and systematics results support the use of B. stenophyllum (Nakai) Kitag. instead of B. falcatum L. to represent the East Asian entity, with 2n =26, and with no observed hybridization or introgression between B. stenophyllum and other species.

4) The revision and treatment of the Bupleurum taxonomy in Northern China was completed, recognizing 26 species and 5 varieties in the region. A new variety was described: B. smithii var. jiaochengense Q. R. Liu & L. H. Wang. Two new combinations were proposed: B. smithii var. parvifolium Shan et Y. Li from variety to species level as B. parvifolium (R. H. Shan & Yin Li) Q. R. Liu & L. H. Wang, and B. sibiricum var. jeholense (Nakai) Chu ex R. H. Shan & Yin Li was treated as a variety of B. chinense DC., B. chinense var. jeholense (Nakai) Q. R. Liu & L. H. Wang. Two names were treated as new synonyms: B. commelynoideum var. flaviflorum R. H. Shan & Yin Li was treated as the synonym of B. parvifolium (R. H. Shan & Yin Li) Q. R. Liu & L. H. Wang; B. gansuense S. L. Pan & P. S. Hsu to B. malconense R. H. Shan & Yin Li. Bupleurum aureum var. breviinvolucratum (Trautv. ex H. Wolff) & Yin Li. was reduced to B. aureum Fisch ex. Hoffm. It was confirmed that B. stenophyllum (Nakai) Kitag. is distributed in Northeast China, and the entities recorded as B. triradiatum Adams ex Hoffm. in China were misidentified as either B. densiflorum Rupr. or B. commelynoideum H. Boissieu.