首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 531 毫秒
1.
Stachys recta L. is a very polymorphous species in which numerous subspecies were recognised. S. recta L. subsp. serpentini (Fiori) Arrigoni is a typical endemism growing on serpentine soils in northern Apennines and particularly in Tuscany (Italy). In order to contribute to a better knowledge of this plant and to its differentiation with respect to S. recta L. subsp. recta, the micromorphological characters (non-glandular and glandular trichomes) and the essential oil composition of the two subspecies were investigated. Micromorphological characters were studied using scanning and transmission electron microscopy, while light microscopy was used for histochemical observations. Essential oil analysis was carried out by gas chromatography and mass spectrometry.In the two examined taxa, the morphology and distribution of glandular and non-glandular trichomes, and the different essential oil composition, may be considered distinctive characters at subspecies level. This is consistent with the taxonomic classification considering S. recta subsp. serpentini a subordinate taxon of S. recta.  相似文献   

2.
Previous taxonomic assessments of the hydrophytic genus Nuphar Sm. (Nymphaeaceae) have inadequately considered the range of morphological variation existing in the genus. A comprehensive statistical analysis of morphological features among the recognized taxa of Nuphar is presented here, first using 10 fruit characters to delimit the separation of two infrageneric groups of taxa, and secondly using 31 characters to quantify the morphological variation found within sect. Nuphar. Results from combined phenetic analyses provided empirical support for recognition of two infrageneric groups of species in the genus (largely by fruit, stigmatic disk margin, neck, and stigmatic disk size) and for separation of taxa within sect. Nuphar (by leaf size, and fruit disk and neck size). Statistical analyses demonstrate that extensive variation in ranges of character states exists among sect. Nuphar taxa. However, a suite of qualitative and quantitative characters can be used to recognize five species and three subspecies within this predominantly Old World assemblage.  相似文献   

3.
Phylogenetic analyses of three cpDNA markers (matK, rpl16, and trnL–trnF) were performed to evaluate previous treatments of Ruteae based on morphology and phytochemistry that contradicted each other, especially regarding the taxonomic status of Haplophyllum and Dictamnus. Trees derived from morphological, phytochemical, and molecular datasets of Ruteae were then compared to look for possible patterns of agreement among them. Furthermore, non-molecular characters were mapped on the molecular phylogeny to identify uniquely derived states and patterns of homoplasy in the morphological and phytochemical datasets. The phylogenetic analyses determined that Haplophyllum and Ruta form reciprocally exclusive monophyletic groups and that Dictamnus is not closely related to the other genera of Ruteae. The different types of datasets were partly incongruent with each other. The discordant phylogenetic patterns between the phytochemical and molecular trees might be best explained in terms of convergence in secondary chemical compounds. Finally, only a few non-molecular synapomorphies provided support for the clades of the molecular tree, while most of the morphological characters traditionally used for taxonomic purposes were found to be homoplasious. Within the context of the phylogenetic relationships supported by molecular data, Ruta, the type genus for the family, can only be diagnosed by using a combination of plesiomorphic, homoplasious, and autapomorphic morphological character states.  相似文献   

4.
Effective conservation that preservesevolutionary entities and processes requiresconservation action that is targeted atappropriate taxonomic units. Molecularphylogenetics can contribute to the resolutionof taxonomic uncertainties by defining therelationships between populations and species,and allowing the recognition of taxonomicentities that reflect evolutionary history.Some uncertainty surrounds the status of taxain the Eucalyptus angustissima complex,which includes threatened taxa with restricteddistributions. The phylogenetic relationshipsbetween populations and taxa in the E.angustissima complex were investigated usingnuclear and chloroplast RFLP analysis.Phylogenetic relationships confirmed thegenetic differentiation of two taxa, identifiedspecies level divergence between two taxacurrently recognised at subspecies level, andestablished the identity of a previouslyundetermined population. Phylogeneticrelationships between the taxa were notcongruent with presumed relationships based onmorphological characters alone.  相似文献   

5.
Vicia ser. Vicia, which includes the Vicia sativa aggregate, was studied by observing morphological variation. The study is an attempt to resolve the taxonomic relationships within the Vicia sativa aggregate by novel investigations along with a synthesis of the results obtained by previous researchers. The study has included some accessions and characters used previously, but has drawn accessions from a wider geographical range than has been attempted previously. Cluster analysis on the basis of 53 morphological characters justified the delimitation of four species within the series and six subspecies within the Vicia sativa aggregate. Accessions from South Asia could easily be incorporated in the classification, but some of the accessions from North Africa showed morphological differences. The morphometric data were coded using the gap weighting method of Thiele (1993) and used in a phylogenetic analysis to study the relationships between the taxa. The phylogenetic analysis, using 33 variables, showed Vicia pyrenaica closely related to Vicia sativa subsp. amphicarpa. A dichotomous key and a multi-access key to aid the identification of the taxa in the series are presented. Received January 21, 2002; accepted November 8, 2002 Published online: March 20, 2003  相似文献   

6.
The loss of orchid habitats has increased the investment on orchid conservation efforts to reduce the risk of extinction of rare species. In northwestern Italy, orchids are among the most threatened of all plant groups in the region, but little is known about the biology of most of the less abundant taxa. In this study, we used light and scanning electron microscopy to characterize the morphology of the seeds of the threatened Orchis patens Desf., a declining species present in semi-natural habitats. We found a marked positive relationship between seed size and embryo size that may be not restricted to O. patens but also occur in other orchid species. The comparative analysis of the observed seed traits revealed hidden morphological affinities at the reproductive level among O. patens and the three subspecies of O. mascula, showing the potential of this approach to test the taxonomic relationships among the different taxa included in the genus Orchis.  相似文献   

7.
Abstract

A comparative study was performed to identify and classify traditional Chinese medicines (TCMs) of the genus Clematis by applying chemometric and numerical methodologies. In the analysis, 12 species representing major TCM plants of the genus and belonging to five different sections – Rectae, Clematis, Meclatis, Tubulosae and Viorna – were identified and demarcated on the basis of morphological and phytochemical characters. In the numerical study (NS), out of 53 selected characters, only 27 phylogenetically informative characters were used for data generation; a phenogram was produced with three distinctive clades. The extent of genetic distances ranged from 0.35 to 0.80. The phytochemical analysis (PA) was conducted using a high performance liquid chromatography coupled with a diode array detector (DAD) and ESI‐MS mode. The compound “Huzhangoside D” (HGD) was the most abundant in the analysed species of the genus. The PA of saponins produced a differential matrix based on the presence or absence of chemical characters, which generated a phenogram. The extent of genetic distances ranged from 0.05 to 0.35 in the phytochemical analysis, with three distinctive clades. Clematis intricata had compounds (HGB, HGD) with GD 0.30, and produced a different pattern of clustering than the previous classification system. The species C. henryi and C. heracleifolia appeared as sister clades having congruent genetic similarity with each other; this is an innovative combination. The classification results of PA and NS approaches corroborate each other, but the chemical fingerprinting method proved more authentic, quick and reliable for the identification and classification of these plant taxa.  相似文献   

8.
The pattern of phenotypic and molecular variation within the polytypic olivaceous warbler H. pallida was examined. This species is distributed in the southern parts of the western Palaearctic, central Asia and in the arid parts of northern Africa, and also in parts of the sub-Saharan Sahel zone. Based on morphology, five subspecies, at times assigned to three groups, have been identified. By comparing morphological, behavioural, vocal and molecular variation, we investigated the phenotypic and phylogenetic relationships within the Hippolais pallida group. The morphological and genetic data of the present study support the view of splitting the olivaceous warbler into a western (former subspecies opaca) and an eastern form (former subspecies elaeica, pallida, reiseri and laeneni). Opaca is consistently and significantly larger than the other taxa in all size measurements, even if it does share morphological properties with elaeica in characters associated with migration. The song of the polytypic pallida differs clearly from that of opaca, and is remarkably consistent within its wide range which comprises four subspecies. The molecular analysis, and the resulting phylogenetic pattern, clearly separated opaca on a single branch distant from the other subspecies. The eastern form consists of two non-overlapping haplotype groups: elaeica with relatively diverse mtDNA variation, and the three African subspecies pallida, reiseri and laeneni, which all share the same or closely related mtDNA haplotypes. It remains open whether the African taxa should be regarded as three valid subspecies of the Eastern olivaceous warbler, or if they are better treated as a single African subspecies.  相似文献   

9.
The phylogeny of the New Zealand hepialid moths was estimated from a cladistic analysis of sixty‐three morphological characters, from all life cycle stages. One hundred and sixteen maximum parsimony trees were produced. The phylogenetic reconstruction indicated that the currently recognized generic concepts, and the four informal lineages hypothesized in a previous morphological taxonomic revision, were monophyletic. The relationships of species within genus Wiseana were not fully resolved. Analysis of a data set of thirty‐nine adult male characters from the New Zealand taxa and the Australian genera Jeana, Oxycanus and Trictena supported the monophyly of the New Zealand ‘Oxycanus’ s.s lineage.  相似文献   

10.
The systematics of the yellow-floweredAconitum lycoctonum species complex (Ranunculaceae) has long been considered difficult because of high morphological variability and hypothesized hybridization. To elucidate the systematic value of these taxa, and to study their phylogeny in a broader context, we studied all species of the subgenusLycoctonum from Europe and the Caucasus Mountains and the European species of the subgen.Aconitum. We sequenced the ITS region and the chloroplast intergenic spacerpsbA-trnH and conducted parsimony analyses. We also measured morphological characters from 19A. lycoctonum populations. The two subgenera in Europe are clearly separated but hybridization between subgenera might have taken place in the past. Sequence variation withinA. lycoctonum and among all taxa of subgenusLycoctonum was very low and probably the result of recent speciation, leading to one morphologically highly variable species in which color morphs could be seen as subspecies. There was high morphological variability within and among populations and the morphological characters have no value as systematic characters.  相似文献   

11.
12.
Fifteen cranial measurements were taken from wild caught specimens ofAlouatta seniculus seniculus, A. s. stramineus andA. s. macconnelli. A morphological analysis showed sex dimorphism in these three groups. A multivariate analysis discriminated among these taxa; males being more clearly discriminated than females. Our data showed that these taxa can be separated on the basis of quantitative cranial traits, biogeographic distribution, karyological differences, and biochemical characters. We therefore propose a new taxonomic arrangement, changing their taxonomic status to the species level (Alouatta seniculus, A. macconnelli, andA. stramineus).  相似文献   

13.
 Variation in isozyme patterns from ten populations of the Korean endemic Lycoris species was used to test the hypothesis that L. flavescens originated from natural hybridization between diploid L. chinensis and L. sanguinea var. koreana. Lycoris sanguinea var. koreana shows fixed heterozygosity at four of nine loci assayed, suggesting that this species is an allotetraploid instead of a diploid. Electrophoretic data suggest that Lycoris flavescens is an allotriploid species derived from the hybridization between diploid L. chinensis and tetraploid L. sanguinea var. koreana. The patterns of allelic distribution in populations of L. flavescens suggest multiple origins of the allotriploid. Within the L. flavescens complex, our isozyme data support the recognition of two taxa, L. flavescens and a recently recognized species, L. uydoensis. Received August 28, 2000 Accepted December 27, 2000  相似文献   

14.
Melica (Poaceae) consist of about 92 species distributed across temperate regions of the world. Within section Dalycum, Melica ciliata sensu lato forms a taxonomic complex of several species and subspecies with clinal morphological variation causing conflicting identifications. To resolve taxonomic confusion, we used three complementary approaches, through molecular, morphological, and phytoecological analyses. The double-digest restriction-associated DNA markers significantly support the monophyly of three taxa: (i) the Mediterranean Melica magnolii, (ii) the Eurasian Melica transsilvanica subsp. transsilvanica, and (iii) the west-European M. ciliata subsp. glauca. This differentiation is corroborated by the analysis of 22 morphometric variables. Furthermore, phytoecological analysis of 221 floristic inventories revealed habitat distinctions among these taxa. Our approach of integrative taxonomy argues for a specific distinction for these three taxa, and we include a key to separate these forms. These new molecular data on the section Dalycum, subsection Ciliatae, call for further phylogenetic analyses including samples of M. ciliata subsp. ciliata and other East-Mediterranean and South African taxa.  相似文献   

15.
Bonaccorso, E., Guayasamin, J. M., Peterson, A. T. & Navarro‐Sigüenza, A. G. (2011). Molecular phylogeny and systematics of Neotropical toucanets in the genus Aulacorhynchus (Aves, Ramphastidae). —Zoologica Scripta, 40, 336–349. We studied the phylogenetic relationships in the genus Aulacorhynchus, an assemblage of Neotropical toucanets distributed from Mexico south to Bolivia. Based on mitochondrial and nuclear DNA characters, we obtained a robust hypothesis of relationships for all recognized species, including good representation of distinct geographic populations. Our results support the monophyly of the genus Aulacorhynchus, but contradict previous taxonomic arrangements. The genus is made up of three major clades: the Aulacorhynchus prasinus complex, Aulacorhynchus huallagae + Aulacorhynchus coeruleicinctis, and Aulacorhynchus haematopygus + Aulacorhynchus sulcatus + Aulacorhynchus derbianus. Andean populations of A. derbianus are more closely related to A. sulcatus than to Pantepuian populations of A. derbianus, rendering A. derbianus paraphyletic. Based on the molecular phylogeny, and information on geographic distributions and morphological and behavioural characters, we review the specific status of these taxa and propose a new taxonomic arrangement within Aulacorhynchus.  相似文献   

16.
In recent years, two major questions concerning the phyletic relationships and systematic position of the douc langurs have arisen. These concern, firstly, the taxonomic level at which the doucs as a group should be distinguished and, secondly, the number of taxa of doucs that should be recognized. It has recently been demonstrated on the basis of an exhaustive phylogenetic analysis that the doucs are generically distinct from the snub-nosed langurs and that they should be referred to as species of Pygathrix and Rhinopithecus, respectively [Jablonski and Peng, Folia Primatologica 60:36–55, 1993]. The present investigation was directed toward testing this conclusion using an expanded data set and a different method of character coding, and toward addressing the question as to the number of species or subspecies of doucs that should be recognized. A wide variety of data from large samples of doucs (n = 38), snub-nosed langurs (n = 53), and an out group (macaques; n = 191) were assembled, coded, and analyzed using an interactive computerized program for phylogenetic analysis. The specimens of Pygathrix examined included skeletal specimens, skins, and, when possible, living animals representing the three recognized taxa of doucs, nemaeus nigripes, and moi. The data base for the study comprised 178 characters, including measurements of skeletal specimens (98 characters), qualitative (presence or absence) morphological features (36 characters), characteristics of the pelage (39 characters), and 5 miscellaneous characters. The conclusions of the study were that 1) as a group, the taxa of Pygathrix preserved a larger number of primitive features for the Pygathrix-Rhino-pithecus clade than did the taxa of Rhinopithecus; 2) the taxa of Pygathrix were less different from one another than are the species of Rhinopithecus were from one another; 3) the subspecies Pygathrix nemaeus moi Kloss, 1926 be synonymized with Pygathrix nemaeus nigripes, as suggested by Napier [Catalogue of Primates in the British Museum (Natural History) and Elsewhere in the British Isles. Port III Family Cercopithecidae, Sub-Family Colobinae. London, 1985]; 4) the extant doucs were best recognized as two subspecies, P. nemaeus nemaeus for the red-shanked douc and P. nemaeus nigripes for the black-shanked douc; and 5) the phylogeny of the doucs and snub-nosed langurs proposed by Jablonski and Peng[op cit.,1993] was found to be robust. © 1995 Wiley-Liss, Inc.  相似文献   

17.
As a first step in determining the identity and relative importance of the evolutionary forces promoting the speciation process in two closely related European taxa of Aquilegia, we investigated the levels of morphological variation in floral and vegetative characters over the narrow region where their ranges enter into contact, and evaluate the relative importance of both types of traits in their differentiation. A total of 12 floral and ten vegetative characters were measured on 375 plants belonging to seven A. vulgaris populations and six A. pyrenaica subsp. cazorlensis populations located in southeastern Spain. Floral and vegetative morphological differentiation occur between taxa and among populations within taxa, but only vegetative characters (particularly plant height and leaf petiolule length) contribute significantly to the discrimination between taxa. Differentiation among populations within taxa is mostly explained by variation in floral traits. Consequently, morphological divergence between the two taxa cannot be interpreted as an extension of among-population differences occurring within taxa. Multivariate vegetative, but not floral, similarity between populations could be predicted from geographical distance. Moreover, the key role of certain vegetative traits in the differentiation of A. vulgaris and A. p. cazorlensis could possibly be attributable to the contrasting habitat requirements and stress tolerance strategies of the two taxa. These preliminary findings seem to disagree with the currently established view of the radiation process in the genus Aquilegia in North America, where the differentiation of floral traits seems to have played a more important role.  相似文献   

18.
19.
Current taxonomic interpretations ofSolanum microdontum Bitter partition the species into two or three infraspecific taxa, variously recognized as subspecies or varieties. The present study reexamines these taxa using morphological data from four individuals each of 69 accessions from most of the range of the species, planted in a common field plot. Our results show that the character states used to recognize infraspecific taxa inS. microdontum often vary within accessions and have no correlation with geography. We conclude that past hypotheses have used typological concepts and that infraspecific taxa are not warranted. This study questions other hypotheses of infraspecific taxa in sect.Petota.  相似文献   

20.
Higher‐level phylogenetics of Pycnogonida has been discussed for many decades but scarcely studied from a cladistic perspective. Traditional taxonomic classifications are yet to be tested and affinities among families and genera are not well understood. Pycnogonida includes more than 1300 species described, but no systematic revisions at any level are available. Previous attempts to propose a phylogeny of the sea spiders were limited in characters and taxon sampling, therefore not allowing a robust test of relationships among lineages. Herein, we present the first comprehensive phylogenetic analysis of the Pycnogonida based on a total evidence approach and Direct Optimization. Sixty‐three pycnogonid species representing all families including fossil taxa were included. For most of the extant taxa more than 6 kb of nuclear and mitochondrial DNA and 78 morphological characters were scored. The most parsimonious hypotheses obtained in equally weighted total evidence analyses show the two most diverse families Ammotheidae and Callipallenidae to be non‐monophyletic. Austrodecidae + Colossendeidae + Pycnogonidae are in the basal most clade, these are morphologically diverse groups of species mostly found in cold waters. The raising of the family Pallenopsidae is supported, while Eurycyde and Ascorhynchus are definitely separated from Ammotheidae. The four fossil taxa are grouped within living Pycnogonida, instead of being an early derived clade. This phylogeny represents a solid framework to work towards the understanding of pycnogonid systematics, providing a data set and a testable hypothesis that indicate those clades that need severe testing, especially some of the deep nodes of the pycnogonid tree and the relationships of ammotheid and callipallenid forms. The inclusion of more rare taxa and additional sources of evidence are necessary for a phylogenetic classification of the Pycnogonida. © The Willi Hennig Society 2006.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号