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1.
翅茎草属(Pterygiella)是中国西南地区特有的半寄生植物.翅茎草属4种植物形态差异不显著,种的界定依据较模糊;此外,杜氏翅茎草2变种的划分依据也存在疑问.本研究选取了翅茎草属4种13个居群,通过数量性状的主成分分析和质量性状的非加权组平均法聚类分析;结合叶绿体4个片段(即atpB-rbcL、trnD-trnT、trnS-trnG和sbA-trnH)和核基因组的ITS片段研究,对该属下的种类划分作了重新界定.研究表明:翅茎草属应包括3种,即翅茎草、杜氏翅茎草和圆茎翅茎草;川滇翅茎木应作为圆茎翅茎草的变种.对杜氏翅茎草指定了后选模式,该种仅包括茎无毛的个体,而茎疏被毛的个体应归入翅茎草中.基于以上研究结果,本文提出了一个新的翅茎草属分种检索表,并做了分类修订.  相似文献   

2.
DNA barcoding is becoming an increasingly popular means to identify species. The obscure discrimination in the genus Pterygiella calls into question the re-assessment of the criterion for species delimitation. We collected 20 individuals, representing all five described species of this genus in its distributional range. The aim was to use three proposed barcode DNA regions (rbcL, matK, and ITS) to diagnose Pterygiella species, and examine which barcode is more suitable for discerning the congeneric and related species. The results showed that the core barcodes matK and rbcL were comparatively less effective. However, the ITS region, especially ITS-1and ITS-2, successfully identified all species in the genus. Furthermore, the secondary structure of ITS-2 RNA, especially compensatory base changes, appears complementary to classical primary sequence analysis for DNA barcoding.  相似文献   

3.
DNA barcoding is becoming an increasingly popular means to identify species. The obscure discrimination in the genus Pterygiella calls into question the re-assessment of the criterion for species delimitation. We collected 20 individuals, representing all five described species of this genus in its distributional range. The aim was to use three proposed barcode DNA regions (rbcL, matK, and ITS) to diagnose Pterygiella species, and examine which barcode is more suitable for discerning the congeneric and related species. The results showed that the core barcodes matK and rbcL were comparatively less effective. However, the ITS region, especially ITS-1 and ITS-2, successfully identified all species in the genus. Furthermore, the secondary structure of ITS-2 RNA, especially compensatory base changes, appears complementary to classical primary sequence analysis for DNA barcoding.  相似文献   

4.
A taxonomic revision of the genus Lasianthus Jack. from Thailand is made based on specimens in BKF, BK, L, AAU, K, BM, E, P, KEP, SING and PSU etc. Three species and three varieties are described as new; a new combination, L. trichophlebus subsp. barbellatus ( Ridley) H. Zhu, is made; eight species and five varieties are found to represent new records to Thailand; seven species, i.e. L. brevidens Craib, L. densifolius Miq., L. incomptus Craib, L. scalaris Craib, L. penicillatus Craib, L. virgatus Craib and L. zambalensis Elmer, axe reduced to synonyms; two species, L. brevipes Craib and L. lowianus King et Gamble are moved to the genus Saprosma; the delimitation of some species is clarified. As a result, fifty-two species, one sub-species and twelve varieties are recognized in the genus Lasianthus from Thailand.  相似文献   

5.
泰国茜草科粗叶木属植物的分类学研究   总被引:4,自引:1,他引:4  
朱华 《植物分类学报》2001,39(2):116-150
在详细检查了K,BM,E,P,AAU,L,KEP,BKF,BK,SING,PSU等标本馆馆藏茜草科粗叶本属Lasianthus Jack.植物标本基础上,研究了泰国产粗叶木属植物的分类学,共归并7个种名,建立3个新种,3 个新变种,1个新等级,以及8个泰国分布新记录种及8个泰国分布新记录变种,确认泰国共有粗叶木属植物52种,1亚种,12变种;讨论了易于混淆的种的界线、它们可能的亲缘关系以及识别要点。  相似文献   

6.
The taxonomical concept of the Paeonia suffruticosa complex i.e. Sect. Moutan Subsect. Vaginatae, has changed greatly since 1990. Six species and four subspecies have been described as new and two subspecies raised to specific level. Five species and two subspecies are recognized in the present revision, viz. P. suffruticosa subsp. suffruticosa and subsp. yinpingmudan, P. jishanensis, P. qiui, P. ostii, P. rockii subsp. rockii and subsp. taibaishanica. P. yananensis, P. ridleyi, P. spontanea, P. moutan subsp. atava, P. suffruticosa subsp. atava, P. rockii subsp. linyanshanii and P. ostii var. lishizhenii are treated as synonyms. P. papaveracea and P. baokangensis are proposed to be interspecific hybrids. A key to the recognized species and subspecies is provided. Biological features of the species are described and their distributions are mapped. The relationships between species are inferred and the origins of commonly cultivated tree peonies ( P. suffruticosa and P. ostii ) are discussed.  相似文献   

7.
8.
The characters that define the genus Kailarsenia (Rubiaceae), namely the stipule morphology, seed-coat perimeter thickening and colporate pollen, are entirely consistent with the morphology of three Australian species placed in that genus. A preliminary cladistic analysis of the genus indicates that the Queensland species K. ochreata and K. jardinei are more closely related to the Bornean K. campanula than to K. suffruticosa an endemic of the Northern Territory, Australia. Kailarsenia suffruticosa has its affinities with the type of the genus K. tentaculata and K. lineata of tropical Asia. The recently described genus, Larsenaikia is reduced to synonomy.  相似文献   

9.
薄唇蕨属的分类研究   总被引:3,自引:2,他引:1  
薄唇蕨属是水龙骨科星蕨类植物中的一个小属,其范围时大时小,没有稳定的概念。我们在编 写《中国植物志》的过程中,分析了该属植物和星蕨类其它属植物的形态和地理分布,扫描了全部种类的孢子,认为薄唇蕨属不同于线蕨属,它包括了过去分出的似薄唇蕨属和树舌蕨等属。  相似文献   

10.
The genus Phlebia has long been regarded as a polyphyletic or paraphyletic taxon, including distinct groups of more closely related species. Consequently, the delimitation of the genus has been given different interpretations and several rearrangements have been proposed by various authors. In the present study, DNA sequences (25S, rDNA) were obtained for twenty species of the genus Phlebia and a phylogenetic analysis was performed. Because of the presumably paraphyletic nature of the genus, different outgroups were used for different sets of taxa. A core group of species, including the type Ph. radiata , is well distinguished. For the delimitation of the genus, however, the wider scope of a more weakly supported clade is proposed. This clade also includes Phlebiopsis gigantea and its combination in Phlebia is reaffirmed. Two species, Ph. griseoflavescens and Ph. tristis , are distinctly separated from this clade and should be removed from the genus. Morphological characters were used in a separate phylogenetic analysis but the result did not conform with analysis from sequence data.  相似文献   

11.
Species of the heterotrophic green microalgal genus Prototheca and related taxa were phylogenetically analyzed based on the nuclear small subunit (SSU) and the 5′ end of the large subunit (LSU) rRNA gene (rDNA) sequences. We propose restricting the genus Prototheca to the four species: P. moriformis Krüger, P. stagnora (Cooke) Pore, P. ulmea Pore, and P. zopfii Krüger. The main diagnostic feature of these taxa is the absence of growth on trehalose.Of these, it was suggested that P. moriformis should be merged into P. zopfii; P. moriformis and three varieties of P. zopfii constituted a paraphyletic assemblage with estimated short evolutionary distances. The trehalose‐assimilating strains (Prototheca wickerhamii Tubaki et Soneda strains and Auxenochlorella protothecoides (Krüger) Kalina et Pun?ochá?ová SAG 211‐7a), together with an invertebrate pathogen Helicosporidium sp., diverged before the radiation of the four species of Prototheca in the SSU rDNA and composite (SSU rDNA plus LSU rDNA) analyses. Comparison between the results from physiological data in this work (fermentative pattern) and those described earlier (growth requirements) lead us to propose a hypothesis that the phenotypic variation, which did not represent diagnostic characters for species delimitation, may reflect the history of genetic diversification within the genus Prototheca as inferred from rDNA sequence characters.  相似文献   

12.
对喜马拉雅和横断山地区特有的水龙骨科的宽带蕨属Platygyria Ching&S.K.Wu植物进行了形态学、分类学、生态和植物地理学的观察与分析,探讨了该属植物的系统位置、亲缘关系和生态适应性,推测宽带蕨属是随着喜马拉雅山脉的隆升,由瓦韦属Lepisorus(J.Sm.)Ching网眼瓦韦群植物适应高寒生态环境演化而来的新生类群。确定宽带蕨属有5种,即川西宽带蕨P.soulieana(Christ)X.C.Zhang&Q.R.Liu、多变宽带蕨P.variabilis Ching&S.K.Wu、耳基宽带  相似文献   

13.
The marine-derived stingrays of Potamotrygonidae, endemic to South American river systems, host an interesting parasite fauna equally related to marine lineages. Among those lineages, the diversity and phylogenetic relationships within Potamotrygonocotyle - a monocotylid monogenoidean specific to potamotrygonids - are poorly known, since 9 of 10 species attributed to this genus have been described in the past 3 years. Here, we readdress the diversity of Potamotrygonocotyle after examining the gills of 436 potamotrygonid individuals representing 12 described and 14 potentially undescribed species of freshwater stingrays from 19 major river systems of South America (i.e. sub-basins). We recognized 12 valid species within the parasite genus, of which four are described in this study. Our taxonomic decisions were based on the phylogenetic analysis of 14 ingroup terminal taxa and 12 morphological characters, which resulted in the following hypothesis of sister-group relationships: ((P. dromedarius, P. tatianae sp. nov.), (P. rionegrense, P. auriculocotyle sp. nov., ((P. quadracotyle, P. umbella), (P. septemcotyle sp. nov., (P. chisholmae, P. uruguayense)), (P. tsalickisi, P. eurypotamoxenus, P. rarum, (P. tocantinsense sp. nov., P. aramasae))))). According to our hypothesis, the absence of autapomorphic features for some nominal species, and the re-evaluation of morphological variation among populations, led us to consider P. eurypotamoxenus and P. uruguayense as junior synonymys of P. tsalicksi and P. chisholmae, respectively. Finally, we address the importance of biogeographic and host representation, in order to fully understand the patterns of morphological variation and host specificity within this group. We found that hypotheses of species delimitation depend greatly on efforts to sample specimens throughout its distributional range and that host specificity within this genus varies dramatically among lineages.  相似文献   

14.
国产赖草属的分类修订   总被引:2,自引:0,他引:2  
蔡联炳  苏旭 《植物研究》2007,27(6):651-660
通过标本研究和野外考察,对中国赖草属(Leymus Hochst.)进行了分类修订。结果在中国共确认了3组、33种、7变种赖草属植物,其中多穗组包含4种,少穗组包含24种、7变种,单穗组包含5种,新报道的3个种和新修订的4个类群(即3个新组合和1个新名称)皆隶于少穗组。同时对赖草属的研究简史、属的形态特征和一些类群的地理分布也分别作了简要介绍。  相似文献   

15.
16.
The African flat lizard genus Platysaurus is widely distributed on rock outcrops in southern Africa and is found both east and west of the Kalahari Desert and between major river drainage systems. We assembled a molecular phylogeny for the genus in order to test several biogeographic hypotheses. Sequence data were obtained from 29 specimens representing 14 taxa of Platysaurus that span the geographic range of the genus. We targeted a fragment of the mitochondrial genome comprising the 3' half of the ND4 gene and most of the flanking tRNA-HSL cluster. The edited alignment comprised 864 characters, of which 479 (55%) were variable and 461 (96%) parsimony informative. Overall, the phylogeny was well resolved and supported by high bootstrap values. Four major clades were identified comprising two to seven species: P. mitchelli and P. maculatus maculatus from the north-eastern range of the genus; P. broadleyi and P. capensis from the western range; P. imperator, P. torquatus, and P. intermedius rhodesianus; P. i. intermedius, P. monotropis, P. minor, P. i. nigrescens, P. lebomboensis, P. i. wilhelmi, and P. o. orientalis. Platysaurus has been suggested to represent a recent adaptive radiation where rapid speciation was fuelled by population fragmentation brought on by vicariant events and possibly divergent sexual selection. The traditional explanation for the radiation of the genus is that the eastern migration of the Kalahari sands fragmented populations in the Plio-Pleistocene, resulting in conditions favorable for speciation. Our genetic data strongly suggests that many of the speciation events in Platysaurus already had occurred prior to the Plio-Pleistocene. Moreover, vicariant events associated with the formation of the major river systems played an additional role in the evolution and distribution of Platysaurus species. Our topology displays long internodes and long terminal branches, suggesting that the radiation is much older than previously believed.  相似文献   

17.
Cortinarius is the most species rich genus of mushroom forming fungi with an estimated 2000 spp. worldwide. However, species delimitation within the genus is often controversial. This is particularly true in the section Calochroi (incl. section Fulvi), where the number of accepted taxa in Europe ranges between c.60 and c.170 according to different taxonomic schools. Here, we evaluated species delimitation within this taxonomically difficult group of species and estimated their phylogenetic relationships. Species were delimited by phylogenetic inference and by comparison of ITS sequence data in combination with morphological characters. A total of 421 ITS sequences were analyzed, including data from 53 type specimens. The phylogenetic relationships of the identified species were estimated by analyzing ITS data in combination with sequence data from the two largest subunits of RNA polymerase II (RPB1 and RPB2). Seventy-nine species were identified, which are believed to constitute the bulk of the diversity of this group in Europe. The delimitation of species based on ITS sequences is more consistent with a conservative morphological species concept for most groups. ITS sequence data from 30 of the 53 types were identical to other taxa, and most of these can be readily treated as synonyms. This emphasizes the importance of critical analysis of collections before describing new taxa. The phylogenetic separation of species was, in general, unambiguous and there is considerable potential for using ITS sequence data as a barcode for the group. A high level of homoplasy and phenotypic plasticity was observed for morphological and ecological characters. Whereas most species and several minor lineages can be recognized by morphological and ecological character states, these same states are poor indicators at higher levels.  相似文献   

18.
19.
摘要:藤山柳属Clematoclethra为中国特有属,属内物种划分争议颇大。利用扫描电镜观察了该属14个居群的花粉形态,结果表明藤山柳属的花粉为小粒花粉,多为圆球形,具三拟孔沟,根据外壁纹饰可分为皱波状花粉、颗粒状花粉和细疣状花粉3种类型。花粉类型与植株毛被特征有一定相关性,对澄清藤山柳属的分类问题具有一定意义。  相似文献   

20.
Delimitation of closely related species is often hindered by the lack of discrete diagnostic morphological characters. This is exemplified in bumblebees (genus Bombus). There have been many attempts to clarify bumblebee taxonomy by using alternative features to discrete morphological characters such as wing shape, DNA, or eco‐chemical traits. Nevertheless each approach has its own limitations. Recent studies have used a multisource approach to gather different lines of speciation evidence in order to draw a strongly supported taxonomic hypothesis in bumblebees. Yet, the resulting taxonomic status is not independent of selected evidence and of consensus methodology (i.e. unanimous procedure, majority, different weighting of evidence). In this article, we compare taxonomic conclusions for a group of taxonomically doubtful species (the Bombus lapidarius‐group) obtained from the four commonly used lines of evidence for species delimitation in bumblebees (geometric morphometric of wing shape, genetic differentiation assessment, sequence‐based species delimitation methods and differentiation of cephalic labial gland secretions). We ultimately aim to assess the usefulness of these lines of evidence as components of an integrative decision framework to delimit bumblebee species. Our results show that analyses based on wing shape do not delineate any obvious cluster. In contrast, nuclear/mitochondrial, sequence‐based species delimitation methods, and analyses based on cephalic labial gland secretions are congruent with each other. This allows setting up an integrative decision framework to establish strongly supported species and subspecies status within bumblebees.  相似文献   

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