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1.
A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pleurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and Arpophyllinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phylogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pleurothallis is not a natural genus and, perhaps may be divided into several discrete genera.  相似文献   

2.
A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pkurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and ArpophyUinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phytogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pkurothallis is not a natural genus and, perhaps may be divided into several discrete genera.  相似文献   

3.
Cladistic analyses of plastid DNA sequences rbcL and trnL-F are presented separately and combined for 48 genera of Amaryllidaceae and 29 genera of related asparagalean families. The combined analysis is the most highly resolved of the three and provides good support for the monophyly of Amaryllidaceae and indicates Agapanthaceae as its sister family. Alliaceae are in turn sister to the Amaryllidaceae/Agapanthaceae clade. The origins of the family appear to be western Gondwanaland (Africa), and infrafamilial relationships are resolved along biogeographic lines. Tribe Amaryllideae, primarily South African, is sister to the rest of Amaryllidaceae; this tribe is supported by numerous morphological synapomorphies as well. The remaining two African tribes of the family, Haemantheae and Cyrtantheae, are well supported, but their position relative to the Australasian Calostemmateae and a large clade comprising the Eurasian and American genera, is not yet clear. The Eurasian and American elements of the family are each monophyletic sister clades. Internal resolution of the Eurasian clade only partially supports currently accepted tribal concepts, and few conclusions can be drawn on the relationships of the genera based on these data. A monophyletic Lycorideae (Central and East Asian) is weakly supported. Galanthus and Leucojum (Galantheae pro parte) are supported as sister genera by the bootstrap. The American clade shows a higher degree of internal resolution. Hippeastreae (minus Griffinia and Worsleya) are well supported, and Zephyranthinae are resolved as a distinct subtribe. An Andean clade marked by a chromosome number of 2n = 46 (and derivatives thereof) is resolved with weak support. The plastid DNA phylogenies are discussed in the context of biogeography and character evolution in the family.  相似文献   

4.
Genetic analysis of isozyme segregation patterns in Layia (Compositae) showed that cytosolic phosphoglucomutase isozymes are encoded by duplicated genes, and that the cytosolic NADP-dependent isocitrate dehydrogenase isozymes are encoded by duplicated genes in species with haploid chromosome numbers of n = 7 and triplicated genes in those with n = 8. The duplicated genes specifying both isozymes assorted independently in all species tested. An electrophoretic survey of phosphoglucomutase in diploid species representing six additional genera of Madiinae, the subtribe to which Layia is assigned, revealed that Achyrachaena, Calycadenia, Hemizonia, Holocarpha, and Madia all possessed duplicated genes. In Lagophylla, one species also had duplicated genes for the isozyme but a second species did not, a loss probably resulting from mutation or chromosomal deletion. The phosphoglucomutase duplication characterizes nearly the entire subtribe and may prove useful to identify phylogenetic relationships between the Madiinae and other subtribes.  相似文献   

5.
Ge S  Li A  Lu BR  Zhang SZ  Hong DY 《American journal of botany》2002,89(12):1967-1972
Phylogenetic relationships were inferred using nucleotide sequences of the chloroplast gene matK for 26 species representing 11 genera of the tribe Oryzeae and three outgroup species. The sequenced fragments varied from 1522 base pairs (bp) to 1534 bp in length with 15.4% variable and 7.9% phylogenetically informative sites when the outgroups were excluded. The aligned sequences were analyzed by maximum parsimony and neighbor-joining methods. Analyses of the sequence data indicated that species of Oryzeae form a strongly supported monophyletic group, concordant with previous morphological and anatomical evidence. The tribe Oryzeae can be divided into two monophyletic lineages, corresponding to the traditionally recognized subtribes Oryzinae and Zizaniinae. The first subtribe consists of Oryza and Leersia, while the subtribe Zizaniinae includes the remaining genera. The matK sequence data did not support the close affinities of the monoecious genera in Oryzeae, implying the possibility of multiple origins of the floral structures in the tribe. It is noteworthy that Porteresia coarctata is closely related to Oryza species, suggesting that it should be treated as a member in the genus Oryza rather than a separate monotypic genus.  相似文献   

6.
The phylogenetic relationships of Silphium and subtribe Engelmanniinae were examined using DNA sequence data. The internal transcribed spacer (ITS) region and the external transcribed spacer (ETS) region were sequenced for 39 specimens representing the six genera of subtribe Engelmanniinae (Berlandiera, Chrysogonum, Dugesia, Engelmannia, Lindheimera, and Silphium), plus five additional genera identified as closely related to the Engelmanniinae by chloroplast DNA restriction site analysis, and three outgroups. Phylogenetic analysis supported the monophyly of Silphium with Lindheimera as sister. Silphium can be divided into two sections based upon two well-supported clades that correspond to root type and growth form. These results also supported the expansion of subtribe Engelmanniinae to include Balsamorhiza, Borrichia, Rojasianthe, Vigethia, and Wyethia. We hypothesize that subtribe Engelmanniinae originated in Mesoamerica and later radiated to the United States. We suggest that the cypsela complex, which is present in Berlandiera, Chrysogonum, Engelmannia, and Lindheimera, arose only once and was subsequently lost in Silphium.  相似文献   

7.
This study represents a preliminary sampling of the pericarp histology of the subtribe Iguanurinae (tribe Areceae, subfamily Arecoideae) of the family Arecaceae. At least one sample from each of the 27 recognized genera was examined and illustrated with a line drawing. This sampling serves to characterize fruit structure in the subtribe as a whole, to illustrate the diversity of pericarp adaptations found in the subtribe, to characterize the monotypic genera, to provide hypotheses about the characterization of the larger genera, and to test existing phylogenetic hypotheses about the Iguanurinae. There are no unique tissues present in the pericarp in this subtribe, but genera can be readily characterized by unique combinations and distributional patterns in common tissues. These patterns, and some prominent evolutionary trends, parallel those in related subtribes of Areceae, such as the Ptychospermatinae and Arecinae. Significant in this subtribe is variation in the distribution of tanniniferous cells, raphide-bearing cells and brachysclereids, in the sculpturing of the seed and the locular epidermis, in the thickness of the locular epidermis, in the thickness of the fibrous vascular bundle sheaths, and especially in the number, orientation and distribution of nonvascular fibrous bundles. One major trend is the formation of systems of separate fibrous bundles and their progressive displacement toward the outer layer of the fruit, where a complex exocarp may form. The diversity of pericarp structure in the Iguanurinae is far greater than in the two subtribes previously studied.  相似文献   

8.
? Premise of the Study: Little research has been done at the molecular level on the tribe Fumarieae (Papaveraceae). Papaveraceae is a model plant group for studying evolutionary patterns despite the lack of a reference phylogeny for this tribe. We investigated the phylogenetic relationships within the tribe to complete the molecular data for this family in order to help understand its character evolution and biogeographic pattern. ? Methods: We used maximum-parsimony and Bayesian approaches to analyze five DNA regions for 25 species representing 10 of the 11 Fumarieae genera and five outgroups. Evolutionary pathways of four characters (habit, life span, type of fruit, and number of seeds per fruit) were inferred on the phylogeny using parsimony. The ancestral distribution areas were reconstructed using dispersal-vicariance analysis. ? Key Results: Fumarieae is monophyletic and includes three groups that agree with the morphology-based subtribes: Discocapninae, Fumariinae, and Sarcocapninae. Within subtribes, the relationships among genera were different from those obtained with morphological data. Annual life span, nonchasmophytic habit, and a several-seeded capsule were the basal character states for the tribe. The ancestor occupied a continuous area between West Eurasia and Africa. Vicariances explain the divergence between lineages Discocapninae (South Africa) and Fumariinae-Sarcocapninae (Mediterranean), and the disjunction of Fumariinae (Mediterranean-Central Asia). ? Conclusions: Molecular phylogeny confirms the subtribal classification of Fumarieae based on morphology. However it provides different results regarding the relationships among genera within each subtribe, which affects the inference of the evolutionary pathway followed by the four selected characters. The disjunct distribution of the tribe is explained by different vicariance scenarios.  相似文献   

9.
The large mistletoe family, Loranthaceae, contains 75 genera, three of which are terrestrial root parasites. The remaining 72 genera are aerial parasites. Four basic haustorial system types are found in aerial genera: epicortical roots (ERs), wood roses, clasping unions and bark strands. The focus of this report is on genera in which ERs are present. Presence of ERs is based on our worldwide collection of haustoria and from literature sources. Our collections include 78% of all aerial genera and 72% of genera with ERs. Collections were analyzed using comparative morphological methods. Of the 72 aerial genera 40 (56%) have ERs and 75% of these are Old World. ERs are the most common haustorial type for Loranthaceae on every major landmass except Africa. Three ER types are described, basal, cauline and adventitious. Basal and adventitious ERs occur in both the Old and New World, whereas cauline ERs are exclusively New World. Adventitious ERs form in a few species in response to injury or epiparasitism. Significant differences occur between basal and cauline ERs in the extent and pattern of elongation, frequency of lateral root formation, and production of haustoria and shoots. Three patterns of axis extension of ERs are recognized, the monochasial sympodium, dichasial sympodium and monopodium. Marked differences in patterns of axis elongation occur between the Old and New World genera analyzed. In Old World taxa 94% of lateral roots contributed to a monochasial sympodium, whereas in New World taxa 84% of root extension was monopodial. Two strategies of resource procurement occur in genera with ERs; the “phalanx” strategy is found in species with basal ERs only, the “guerilla” strategy in New World species with cauline ERs. Species with ERs have the potential for clonal growth through fragmentation of stems, ERs, or both, but the extent of clonal growth in nature is unknown. The large number and wide distribution of genera with ERs add support to the hypothesis that the presence of ERs is an ancestral trait for aerial Loranthaceae.  相似文献   

10.
? Premise of the study: The mint family (Lamiaceae) is the sixth largest family of flowering plants, with the tribe Mentheae containing about a third of the species. We present a detailed perspective on the evolution of the tribe Mentheae based on a phylogenetic analysis of cpDNA and nrDNA that is the most comprehensive to date, a biogeographic set of analyses using a fossil-calibrated chronogram, and an examination of staminal evolution. ? Methods: Data from four cpDNA and two nrDNA markers representing all extant genera within the tribe Mentheae were analyzed using the programs BEAST, Lagrange, S-DIVA, and BayesTraits. BEAST was used to simultaneously estimate phylogeny and divergence times, Lagrange and S-DIVA were used for biogeographical reconstruction, and BayesTraits was used to infer staminal evolution within the tribe. ? Key results: Currently accepted subtribal delimitations are shown to be invalid and are updated. The Mentheae and all five of its subtribes have a Mediterranean origin and have dispersed to the New World multiple times. The vast majority of New World species of subtribe Menthinae are the product of a single dispersal event in the mid-late Miocene. At least four transitions from four stamens to two stamens have occurred within Mentheae, once in the subtribe Salviinae, once in the subtribe Lycopinae, and at least twice in the subtribe Menthinae. ? Conclusions: Worldwide cooling trends probably played a large role in the diversification and present day distribution of the tribe Mentheae. Additional work is needed to ascertain relationships within some Mentheae genera, especially in the subtribe Menthinae.  相似文献   

11.
Asteraceae are the largest family in southern Africa. Elucidating its origins and radiation in the region requires well-supported species-level phylogenies of the lineages. This paper presents a phylogenetic framework for subtribe Arctotidinae, which have a southern and eastern African-Australian distribution centered in the winter-rainfall region of South Africa. DNA sequence data from five chloroplast fragments (ndhF, psbA-trnH, rps16, trnS-trnfM, and trnT-trnF) and the nuclear ITS region were analyzed separately and in combination using parsimony and Bayesian methods. The data sets comprised exemplars from 18 ingroup species, representing the five currently accepted genera, and four outgroup species from Gorteriinae. All analyses indicated Arctotis and Haplocarpha are polyphyletic as presently circumscribed. The Australian-endemic Cymbonotus lawsonianus was placed within a strongly supported clade also containing A. arctotoides from South Africa and H. schimperi from eastern Africa. Retention of Dymondia and resurrection of Landtia at generic level are strongly supported. The phylogenetic hypotheses indicate the subtribe might have originated in temperate southern or eastern Africa, or it was ancestrally widespread in southern Africa and has diversified vicariously. The derived placement of C. lawsonianus indicates long-distance dispersal from southern Africa to Australia occurred.  相似文献   

12.
Phylogenetic relationships among 76 species of Oleaceae, representing all 25 recognized genera of the family, were assessed by a cladistic analysis of DNA sequences from two noncoding chloroplast loci, the rps16 intron and the trnL-F region. Consensus trees from separate and combined analyses are congruent and agree well with nonmolecular data (chromosome numbers, fruit and wood anatomy, leaf glycosides, and iridoids). The two debated genera Dimetra and Nyctanthes, previously suggested to belong to Verbenaceae (sensu lato) or Nyctanthaceae, are shown to belong to Oleaceae, sister to the hitherto genus incertae sedis Myxopyrum. This clade is also supported by anatomical and chemical data. The subfamily Jasminoideae is paraphyletic, and a new classification is presented. The subfamily level is abandoned, and the former Jasminoideae is split into four tribes: Myxopyreae (Myxopyrum, Nyctanthes, and Dimetra), Fontanesieae (Fontanesia), Forsythieae (Abeliophyllum and Forsythia), and Jasmineae (Jasminum and Menodora). The tribe Oleeae (previous subfamily Oleoideae) is clearly monophyletic, comprising the subtribes Ligustrinae (Syringa and Ligustrum), Schreberinae status novus (Schrebera and Comoranthus), Fraxininae status novus (Fraxinus), and Oleinae (12 drupaceous genera). An rps16 sequence obtained from Hesperelaea, known only from the type specimen collected in 1875, confirmed the placement of this extinct taxon in the subtribe Oleinae.  相似文献   

13.
The tribe Arctotideae (African Daisies), of the flowering plant family Compositae (Asteraceae), is a diverse and interesting group with a primarily southern African distribution (ca. 13 genera, 215 species) and many species in the Cape Floristic Region. It is divided into two subtribes: Arctotidinae (ca. 5 genera, 85 species) and Gorteriinae (ca. 8 genera, 130 species). The monophyly of the genera within the subtribe Gorteriinae and their relationship to one another was investigated using 71 samples/212 sequences including 64/141 of which are newly reported from three phylogenetic markers, two from chloroplast DNA (trnL-F and ndhF) and one from the nuclear genome (ITS). The outgroup was composed of seven members from the sister subtribe. Results show the subtribe Gorteriinae to be divided into three monophyletic groups, the Gazania-Hirpicium-Gorteria group, the Didelta group, and the Berkheya-Cullumia group. Within these three groups are 13 sub-groups, one of which has sub-clades. The genus Berkheya Ehrh. is paraphyletic, falling into five different sub-groups. The two monotypic genera, Cuspidia and Heterorhachis are not nested within any of the Berkheya clades. Hirpicium and Cullumia each have most of their taxa in a monophyletic group, but they also have one or two taxa associated with other clades. Four of the five sub-groups of Berkheya have morphologically recognizable shared characters, such as habit and spines that have been recognized by past studies. However, the grouping of one species with Didelta is difficult to explain. Support for the major clades and most of the sub-groups is strong but the relationships among some of the terminal taxa are variable.  相似文献   

14.
With efficient sequencing techniques, full mitochondrial genomes are rapidly replacing other widely used markers, such as the nuclear rRNA genes, for phylogenetic analysis but their power to resolve deep levels of the tree remains controversial. We studied phylogenetic relationships of leaf beetles (Chrysomelidae) in the tribes Galerucini and Alticini (root worms and flea beetles) based on full mitochondrial genomes (103 newly sequenced), and compared their performance to the widely sequenced nuclear rRNA genes (full 18S, partial 28S). Our results show that: (i) the mitogenome is phylogenetically informative from subtribe to family level, and the per‐nucleotide contribution to nodal support is higher than that of rRNA genes, (ii) the Galerucini and Alticini are reciprocally monophyletic sister groups, if the classification is adjusted to accommodate several ‘problematic genera’ that do not fit the dichotomy of lineages based on the presence (Alticini) or absence (Galerucini) of the jumping apparatus, and (iii) the phylogenetic results suggest a new classification system of Galerucini with eight subtribes: Oidina, Galerucina, Hylaspina, Metacyclina, Luperina, Aulacophorina, Diabroticina and Monoleptina.  相似文献   

15.
A. Spencer Tomb 《Brittonia》1974,26(2):203-216
Chromosome numbers are reported from over 230 populations representing species in eight genera. First counts are reported for three species ofStephanomeria, five species ofLygodesmia, and one species ofPinaropappus. Base chromosome numbers,x = 6, 7, 8, and 9 are known in the subtribe;x = 9 is found in six of the 12 genera and presumably is the ancestral base number for the subtribe. Two phyletic lines, aMalacothrix line and aStephanomeria line are recognized on morphological grounds. A key to the 12 genera is provided.  相似文献   

16.
Abstract: Sequences of the internal transcribed spacers (ITS1 and ITS2) of nuclear ribosomal DNA were analysed for 44 Artemisia species (46 populations) representing all the five classical subgenera and the geographical range of the genus, 11 species from 10 genera closely related to Artemisia, and six outgroup species from five other genera of the Anthemideae. The results definitely support the monophyly of the genus Artemisia in its broadest sense (including some taxa segregated as independent genera, like Oligosporus and Seriphidium ). Eight main clades are established in this molecular phylogeny within Artemisia; they agree in part with the classical subdivision of the genus, but they also suggest that some infrageneric groups must be redefined, especially the subgenus Artemisia. The subgenera Tridentatae and Seriphidium are independent from each other. Some of the satellite genera are clearly placed within Artemisia ( Artemisiastrum, Filifolium, Mausolea, Picrothamnus, Sphaeromeria, Turaniphytum ), whereas some others fall outside the large clade formed by this genus (Brachanthemum, Elachanthemum, Hippolytia, Kaschgaria). Our results, correlated to other data such as pollen morphology, allow us to conclude that the subtribe Artemisiinae as currently defined is a very heterogeneous group. Affinities of the largest genus of the subtribe and tribe, Artemisia, and of other genera of the subtribe to some genera from other subtribes of the Anthemideae strongly suggest that subtribe Artemisiinae needs a deep revision and redefinition. Phylogenetic utility of region trnL-F of the plastid DNA in the genus Artemisia and allies was also evaluated: sequences of the trnL-F region in Artemisia do not provide phylogenetic information.  相似文献   

17.
Tilosomes, also called “fibrous bodies” or “rod bodies” in older literature, are lignified excrescences from the walls of cells of the innermost velamen cell layer adjacent to thin-walled passage cells of the exodermis in roots of many epiphytic orchids. Seven broad morphological types are recognized: spongy, lamellate, discoid, webbed, meshed, baculate, and plaited. Some types characterize specific genera or subtribes of Orchidaceae. Of the 350 species in 175 genera included in a survey of the family, tilosomes occur in 95 species and 39 genera and are concentrated in tribe Polystachyeae and subtribes Sobraliinae, Coelogyninae, Laeliinae, Pleurothallidinae, Bulbophyllinae, Lycastinae, and Maxillariinae. With the exception of the pantropical genera Bulbophyllum and Polystachya and the Paleotropical subtribe Coelogyninae, tilosomes are almost exclusively Neotropical phenomena.  相似文献   

18.
The Loranthaceae is the largest plant family with aerial branch parasites termed mistletoes. Three genera of Loranthaceae are terrestrial root parasites and the remaining 72 genera are aerial parasites. Several characters, including habit, haustorial type, germination pattern, pollen morphology, chromosome number, inflorescence morphology and flower merosity, fusion, symmetry and size, are considered to reflect evolutionary relationships within the family. Convergence is a common evolutionary pattern and can confound interpretations of evolution. We investigated character evolution by mapping character states onto a phylogenetic tree based on the nuclear ITS and chloroplast trnL–trnF regions. Convergences in form were found in several characters, including habit, haustorial type, flower symmetry and merosity. These convergences typically correspond to ecological parameters such as pollination syndrome or stresses associated with the canopy habit. Other characters such as chromosome number and germination pattern illustrate divergent evolution among clades.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 101–113.  相似文献   

19.
20.
The lichen moth tribe Lithosiini is best known for its hypothesized larval feeding behaviour, lichenivory. The larvae of some species have been found to be capable of sequestering polyphenolics, and the adults of some species are unpalatable to vertebrate predators. However, the chemical basis for the defence is unknown. Here we reconstruct a phylogenetic hypothesis using likelihood methods (maximum likelihood, Bayesian inference) for 65 species of Lithosiini representing 37 genera and seven outgroup species using 2806 bp of sequence data obtained from two mitochondrial gene fragments (COI barcoding region, CytB), and two nuclear gene fragments (RpS5 and ribosomal gene region 28S). Lithosiine species representing four of the seven subtribes and unplaced taxa are included in the analysis. The deeper relationships within the tribe are not strongly supported, and the monophyly of three of the four subtribes is not supported. The placement of the fourth subtribe, Acsalina, is weakly supported. We also conduct a survey of the secondary metabolites present within adults of five species. The species are examined for the presence of lichen polyphenolics and plant secondary metabolites sequestered by arctiines. Seven lichen polyphenolics are identified in the taxa examined, but no plant secondary metabolites are found using either analytical method. The results of this study and prior reports in the literature of chemical sequestration and unpalatability are plotted onto the resulting Bayesian inference phylogeny to examine the evolution of chemical defence within Lithosiini. Species that sequester lichen polyphenolics and unpalatable species occur in each of the major clades recovered in the analysis.  相似文献   

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