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Stephen R. Downie - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic Analysis Reveals Multiple Cases of Morphological Parallelism and Taxonomic Polyphyly in Lomatium (Apiaceae)
Systematic Botany, 2014Co-Authors: Emma E. George, Ronald L. Hartman, Stephen R. Downie, Donald H. Mansfield, James F. Smith, Cody E. HinchliffAbstract:Abstract The genera Lomatium and Cymopterus, along with many others, form a group that has been referred to previously as the perennial endemic Apiaceae subfamily Apioideae of western North America. This group of ecologically important and widespread species has been the target of numerous systematic studies, but the evolutionary relationships among these species remain elusive. Here we show that this confusion is due to high levels of morphological parallelism and homoplasy in the characters that have traditionally been used to define them, a result that is concordant with previous studies of the group. We explore patterns of evolution in traditionally important morphological characters using Bayesian stochastic character mapping on a phylogeny constructed from novel nrDNA and cpDNA sequence data for 96 specific and infraspecific taxa of the estimated 200 species in the group. We consider the implications of these results for taxonomic classification, the evolution of morphologies, and the utility of the...
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a multivariate analysis of Cymopterus glomeratus formerly known as c acaulis apiaceae
Rhodora, 2005Co-Authors: Geoffrey A Levin, Feng Jie Sun, Stephen R. DownieAbstract:Abstract Five infraspecific taxa have been recognized in Cymopterus glomeratus (= C. acaulis): vars. glomeratus (= acaulis), fendleri, greeleyorum, higginsii, and parvus. The results of previous phylogenetic analyses of DNA sequence and morphological data have supported the close association of these five varieties, although the relationships among them could not be discerned. The recognition of infraspecific taxa within C. glomeratus is controversial. Multivariate analysis of variance and principal component analysis of 288 specimens representing the morphological variability and geographic distribution of this species complex were conducted to test the validity of these infraspecific taxa. Results show that most of the characters previously used to recognize these varieties are highly variable within the taxa. Although analysis of variance demonstrated some statistical differences among the varieties, patterns were not consistent. No clearly separated clusters are revealed in the principal component ana...
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An ITS-Based Phylogenetic Analysis of the Perennial, Endemic Apiaceae Subfamily Apioideae of Western North America
Systematic Botany, 2004Co-Authors: Feng Jie Sun, Stephen R. Downie, Ronald L. HartmanAbstract:Phylogenetic analyses of 159 DNA sequences from the nuclear rDNAinternal transcribedspacer regionwere conducted to evaluate the monophyly of the herbaceous, perennial genera of Apiaceae subfamily Apioideae endemic to North America (north of Mexico) and to determine the relationships of those elements that currently comprise Cymopterus within the group. The results of a previous phylogenetic study were equivocal in suggesting monophylyfor theseperennial, endemic taxa and revealed Cymopterus to be polyphyletic, with its species closely linked with those of Aletes, Lomatium, Musineon, Oreoxis, Orogenia, Podistera, PseudoCymopterus , Pteryxia, and Tauschia. Herein, we expand sampling to include com- prehensive representation of Aletes, Cymopterus, Musineon, Oreoxis, Orogenia, Podistera, PseudoCymopterus , and Pteryxia, and greater representation of Lomatiumand Tauschia. We alsoinclude all members of twogeneranot examinedpreviously, Glehnia and Oreonana, as well as additional outgroup genera from the Angelica clade of the apioid superclade. Our results indicate that the perennial, endemic apioid umbellifers of North America constitute a (weakly supported) monophyleticgroup, with Angelica and the meso-American Arracacia clade comprising two of several possible sister groups. The two subspecies of Glehnia littoralis ally with Angelica and Peucedanum japonicum ; Oreonana shows afe nity with several species of Cymopterusand Lomatium. The lack of resolution in the ITS trees precludes unambiguous hypotheses of relationship among these perennial, endemic umbellifers but does show that many of these genera, where resolved, are not monophyletic. Indeed, Cymopterus and Lomatium are highly polyphyletic and permeate all major clades resolved in the molecule-derived trees. Evidence from branch lengths and low sequence divergence suggests that this group of North American umbellifers underwent rapid radiation, likely during the geoclimatic events of the Late Tertiary and Quaternary. Cymopterus Raf. (Apiaceae subfamily Apioideae), the spring-parsleys, comprises some 35 species (Kar- tesz 1994) of herbaceous perennials distributed largely throughout western North America (NA). Approxi- mately two-thirds of these species are restricted to the Great Basinregion, roughly boundedbythe SnakeRiv- er of Idaho, Sierra Nevada of California, Colorado Riv- er of Arizona, and the Rocky Mountains of Colorado (Mathias 1965). Many species are xerophytic or semi- xerophytic, being cone ned to dry, sandy, or alkaline habitats. They are low in stature, possess thickened, deep taproots, and have ternately cleft, compound or dissected leaves. The ine orescence is an open com- pound umbel, and the e owers are mostly yellow or white, opening from very early in the spring to throughout the summer. Most distinctive, however, is their fruit, for the two marginal (lateral), and usually one or more of the three dorsal ribs, are conspicuously winged. These wings may be membranous to spongy- corky, and variously plane to wavy or corrugated. In- deed, the generic name is derived from the Greek kyma, a wave, and pteron, a wing, referring to the often undulate wings of the fruit.
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A molecular systematic investigation of Cymopterus and its allies (Apiaceae) based on phylogenetic analyses of nuclear (ITS) and plastid (rps16 intron) DNA sequences
South African Journal of Botany, 2004Co-Authors: F.-j. Sun, Stephen R. Downie, B.-e. Van Wyk, Patricia M. TilneyAbstract:Considerable controversy exists with regard to the proper delimitation of Cymopterus (Apiaceae subfamily Apioideae) and its relationship to the other perennial endemic umbellifers of western North America. Previous molecular systematic studies using nuclear (rDNA ITS) and, for subsets of taxa, plastid (rps16 intron and trnF-trnL-trnT) DNA sequences have revealed that the genus Cymopterus is polyphyletic, with its species inextricably linked with those of Aletes, Lomatium, Musineon, Oreoxis, PseudoCymopterus, Pteryxia, Tauschia, and several other genera of the region. Herein, in an effort to increase resolution of relationships, we procured rps16 intron sequence data from 74 accessions of Cymopterus and its allies so that ITS and intron matrices are available for the same set of 129 taxa. These data matrices were analysed, separately and in combination, using maximum parsimony and (or) maximum likelihood methods. For those trees exhibiting the greatest resolution, the results revealed that the perennial, endemic apioid genera of North America (north of Mexico) comprise a weakly supported monophyletic group, with Angelica constituting its sister lineage. Cymopterus is confirmed as highly polyphyletic. The rps16 intron yielded substantially fewer parsimony informative characters than those of the ITS region and when analysed, separately or in combination, with ITS data, resulted in trees of poor resolution. Only one previously identified species group of Cymopterus is supported as monophyletic; this group coincides with section Phellopterus, and is recognised by its showy, basally connate bractlets. Many other genera endemic to western North America appear to be highly artificial assemblages of species that will likely be abandoned in any revised system of umbellifer classification.
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Polyphyly of the spring-parsleys (Cymopterus): molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western North American Apiaceae
Canadian Journal of Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S. Katz-downieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and composition and orientation of mericarp compression are highly variable. The results of these analyses reveal that Cymopterus and Lomatium, the two largest genera of western North American Apiaceae, are polyphyletic, and that their species are inextricably linked with those of other endemic perennial genera of the region (such as, Aletes, Musineon, Oreoxis, PseudoCymopterus, Pteryxia, and Tauschia), many of which are also not monophyletic. Prior emphasis on characters of the fruit in all systems of classification of the group has led to highly artificial assemblages of species. A complete reassessment of generic limits of all western endemic Apiaceae is required, as is further systematic study of this intractable group.Key words: Apiaceae, Cymopterus, phylogeny, ITS, rps16 intron, morphology.
Ronald L. Hartman - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic Analysis Reveals Multiple Cases of Morphological Parallelism and Taxonomic Polyphyly in Lomatium (Apiaceae)
Systematic Botany, 2014Co-Authors: Emma E. George, Ronald L. Hartman, Stephen R. Downie, Donald H. Mansfield, James F. Smith, Cody E. HinchliffAbstract:Abstract The genera Lomatium and Cymopterus, along with many others, form a group that has been referred to previously as the perennial endemic Apiaceae subfamily Apioideae of western North America. This group of ecologically important and widespread species has been the target of numerous systematic studies, but the evolutionary relationships among these species remain elusive. Here we show that this confusion is due to high levels of morphological parallelism and homoplasy in the characters that have traditionally been used to define them, a result that is concordant with previous studies of the group. We explore patterns of evolution in traditionally important morphological characters using Bayesian stochastic character mapping on a phylogeny constructed from novel nrDNA and cpDNA sequence data for 96 specific and infraspecific taxa of the estimated 200 species in the group. We consider the implications of these results for taxonomic classification, the evolution of morphologies, and the utility of the...
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An ITS-Based Phylogenetic Analysis of the Perennial, Endemic Apiaceae Subfamily Apioideae of Western North America
Systematic Botany, 2004Co-Authors: Feng Jie Sun, Stephen R. Downie, Ronald L. HartmanAbstract:Phylogenetic analyses of 159 DNA sequences from the nuclear rDNAinternal transcribedspacer regionwere conducted to evaluate the monophyly of the herbaceous, perennial genera of Apiaceae subfamily Apioideae endemic to North America (north of Mexico) and to determine the relationships of those elements that currently comprise Cymopterus within the group. The results of a previous phylogenetic study were equivocal in suggesting monophylyfor theseperennial, endemic taxa and revealed Cymopterus to be polyphyletic, with its species closely linked with those of Aletes, Lomatium, Musineon, Oreoxis, Orogenia, Podistera, PseudoCymopterus , Pteryxia, and Tauschia. Herein, we expand sampling to include com- prehensive representation of Aletes, Cymopterus, Musineon, Oreoxis, Orogenia, Podistera, PseudoCymopterus , and Pteryxia, and greater representation of Lomatiumand Tauschia. We alsoinclude all members of twogeneranot examinedpreviously, Glehnia and Oreonana, as well as additional outgroup genera from the Angelica clade of the apioid superclade. Our results indicate that the perennial, endemic apioid umbellifers of North America constitute a (weakly supported) monophyleticgroup, with Angelica and the meso-American Arracacia clade comprising two of several possible sister groups. The two subspecies of Glehnia littoralis ally with Angelica and Peucedanum japonicum ; Oreonana shows afe nity with several species of Cymopterusand Lomatium. The lack of resolution in the ITS trees precludes unambiguous hypotheses of relationship among these perennial, endemic umbellifers but does show that many of these genera, where resolved, are not monophyletic. Indeed, Cymopterus and Lomatium are highly polyphyletic and permeate all major clades resolved in the molecule-derived trees. Evidence from branch lengths and low sequence divergence suggests that this group of North American umbellifers underwent rapid radiation, likely during the geoclimatic events of the Late Tertiary and Quaternary. Cymopterus Raf. (Apiaceae subfamily Apioideae), the spring-parsleys, comprises some 35 species (Kar- tesz 1994) of herbaceous perennials distributed largely throughout western North America (NA). Approxi- mately two-thirds of these species are restricted to the Great Basinregion, roughly boundedbythe SnakeRiv- er of Idaho, Sierra Nevada of California, Colorado Riv- er of Arizona, and the Rocky Mountains of Colorado (Mathias 1965). Many species are xerophytic or semi- xerophytic, being cone ned to dry, sandy, or alkaline habitats. They are low in stature, possess thickened, deep taproots, and have ternately cleft, compound or dissected leaves. The ine orescence is an open com- pound umbel, and the e owers are mostly yellow or white, opening from very early in the spring to throughout the summer. Most distinctive, however, is their fruit, for the two marginal (lateral), and usually one or more of the three dorsal ribs, are conspicuously winged. These wings may be membranous to spongy- corky, and variously plane to wavy or corrugated. In- deed, the generic name is derived from the Greek kyma, a wave, and pteron, a wing, referring to the often undulate wings of the fruit.
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Polyphyly of the spring-parsleys (Cymopterus): molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western North American Apiaceae
Canadian Journal of Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S. Katz-downieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and composition and orientation of mericarp compression are highly variable. The results of these analyses reveal that Cymopterus and Lomatium, the two largest genera of western North American Apiaceae, are polyphyletic, and that their species are inextricably linked with those of other endemic perennial genera of the region (such as, Aletes, Musineon, Oreoxis, PseudoCymopterus, Pteryxia, and Tauschia), many of which are also not monophyletic. Prior emphasis on characters of the fruit in all systems of classification of the group has led to highly artificial assemblages of species. A complete reassessment of generic limits of all western endemic Apiaceae is required, as is further systematic study of this intractable group.Key words: Apiaceae, Cymopterus, phylogeny, ITS, rps16 intron, morphology.
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polyphyly of the spring parsleys Cymopterus molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western north american apiaceae
Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S KatzdownieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and compo...
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A new species of Cymopterus (Apiaceae) from the Rocky Mountain region, U.S.A.
Brittonia, 2000Co-Authors: Ronald L. HartmanAbstract:Cymopterus constancei is described as new from mostly western portions of Wyoming, Colorado, and New Mexico and from eastern Utah and Arizona. It has been confused with C. bulbosus A. Nelson but differs in several features of its bractlets, phenology, and habitat. The novelty is among the earliest of the native flora to bloom and is quite uniform morphologically. The number of collections encountered exceeds 200, a fourfold increase, in the past 22 years.
Feng Jie Sun - One of the best experts on this subject based on the ideXlab platform.
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a multivariate analysis of Cymopterus glomeratus formerly known as c acaulis apiaceae
Rhodora, 2005Co-Authors: Geoffrey A Levin, Feng Jie Sun, Stephen R. DownieAbstract:Abstract Five infraspecific taxa have been recognized in Cymopterus glomeratus (= C. acaulis): vars. glomeratus (= acaulis), fendleri, greeleyorum, higginsii, and parvus. The results of previous phylogenetic analyses of DNA sequence and morphological data have supported the close association of these five varieties, although the relationships among them could not be discerned. The recognition of infraspecific taxa within C. glomeratus is controversial. Multivariate analysis of variance and principal component analysis of 288 specimens representing the morphological variability and geographic distribution of this species complex were conducted to test the validity of these infraspecific taxa. Results show that most of the characters previously used to recognize these varieties are highly variable within the taxa. Although analysis of variance demonstrated some statistical differences among the varieties, patterns were not consistent. No clearly separated clusters are revealed in the principal component ana...
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An ITS-Based Phylogenetic Analysis of the Perennial, Endemic Apiaceae Subfamily Apioideae of Western North America
Systematic Botany, 2004Co-Authors: Feng Jie Sun, Stephen R. Downie, Ronald L. HartmanAbstract:Phylogenetic analyses of 159 DNA sequences from the nuclear rDNAinternal transcribedspacer regionwere conducted to evaluate the monophyly of the herbaceous, perennial genera of Apiaceae subfamily Apioideae endemic to North America (north of Mexico) and to determine the relationships of those elements that currently comprise Cymopterus within the group. The results of a previous phylogenetic study were equivocal in suggesting monophylyfor theseperennial, endemic taxa and revealed Cymopterus to be polyphyletic, with its species closely linked with those of Aletes, Lomatium, Musineon, Oreoxis, Orogenia, Podistera, PseudoCymopterus , Pteryxia, and Tauschia. Herein, we expand sampling to include com- prehensive representation of Aletes, Cymopterus, Musineon, Oreoxis, Orogenia, Podistera, PseudoCymopterus , and Pteryxia, and greater representation of Lomatiumand Tauschia. We alsoinclude all members of twogeneranot examinedpreviously, Glehnia and Oreonana, as well as additional outgroup genera from the Angelica clade of the apioid superclade. Our results indicate that the perennial, endemic apioid umbellifers of North America constitute a (weakly supported) monophyleticgroup, with Angelica and the meso-American Arracacia clade comprising two of several possible sister groups. The two subspecies of Glehnia littoralis ally with Angelica and Peucedanum japonicum ; Oreonana shows afe nity with several species of Cymopterusand Lomatium. The lack of resolution in the ITS trees precludes unambiguous hypotheses of relationship among these perennial, endemic umbellifers but does show that many of these genera, where resolved, are not monophyletic. Indeed, Cymopterus and Lomatium are highly polyphyletic and permeate all major clades resolved in the molecule-derived trees. Evidence from branch lengths and low sequence divergence suggests that this group of North American umbellifers underwent rapid radiation, likely during the geoclimatic events of the Late Tertiary and Quaternary. Cymopterus Raf. (Apiaceae subfamily Apioideae), the spring-parsleys, comprises some 35 species (Kar- tesz 1994) of herbaceous perennials distributed largely throughout western North America (NA). Approxi- mately two-thirds of these species are restricted to the Great Basinregion, roughly boundedbythe SnakeRiv- er of Idaho, Sierra Nevada of California, Colorado Riv- er of Arizona, and the Rocky Mountains of Colorado (Mathias 1965). Many species are xerophytic or semi- xerophytic, being cone ned to dry, sandy, or alkaline habitats. They are low in stature, possess thickened, deep taproots, and have ternately cleft, compound or dissected leaves. The ine orescence is an open com- pound umbel, and the e owers are mostly yellow or white, opening from very early in the spring to throughout the summer. Most distinctive, however, is their fruit, for the two marginal (lateral), and usually one or more of the three dorsal ribs, are conspicuously winged. These wings may be membranous to spongy- corky, and variously plane to wavy or corrugated. In- deed, the generic name is derived from the Greek kyma, a wave, and pteron, a wing, referring to the often undulate wings of the fruit.
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Polyphyly of the spring-parsleys (Cymopterus): molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western North American Apiaceae
Canadian Journal of Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S. Katz-downieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and composition and orientation of mericarp compression are highly variable. The results of these analyses reveal that Cymopterus and Lomatium, the two largest genera of western North American Apiaceae, are polyphyletic, and that their species are inextricably linked with those of other endemic perennial genera of the region (such as, Aletes, Musineon, Oreoxis, PseudoCymopterus, Pteryxia, and Tauschia), many of which are also not monophyletic. Prior emphasis on characters of the fruit in all systems of classification of the group has led to highly artificial assemblages of species. A complete reassessment of generic limits of all western endemic Apiaceae is required, as is further systematic study of this intractable group.Key words: Apiaceae, Cymopterus, phylogeny, ITS, rps16 intron, morphology.
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polyphyly of the spring parsleys Cymopterus molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western north american apiaceae
Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S KatzdownieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and compo...
Deborah S. Katz-downie - One of the best experts on this subject based on the ideXlab platform.
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Polyphyly of the spring-parsleys (Cymopterus): molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western North American Apiaceae
Canadian Journal of Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S. Katz-downieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and composition and orientation of mericarp compression are highly variable. The results of these analyses reveal that Cymopterus and Lomatium, the two largest genera of western North American Apiaceae, are polyphyletic, and that their species are inextricably linked with those of other endemic perennial genera of the region (such as, Aletes, Musineon, Oreoxis, PseudoCymopterus, Pteryxia, and Tauschia), many of which are also not monophyletic. Prior emphasis on characters of the fruit in all systems of classification of the group has led to highly artificial assemblages of species. A complete reassessment of generic limits of all western endemic Apiaceae is required, as is further systematic study of this intractable group.Key words: Apiaceae, Cymopterus, phylogeny, ITS, rps16 intron, morphology.
Deborah S Katzdownie - One of the best experts on this subject based on the ideXlab platform.
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polyphyly of the spring parsleys Cymopterus molecular and morphological evidence suggests complex relationships among the perennial endemic genera of western north american apiaceae
Botany, 2002Co-Authors: Stephen R. Downie, Ronald L. Hartman, Feng Jie Sun, Deborah S KatzdownieAbstract:Cladistic analyses of DNA sequences from the nuclear rDNA internal transcribed spacer region and cpDNA rps16 intron and, for a subset of taxa, the cpDNA trnF-trnL-trnT locus were carried out to evaluate the monophyly of Cymopterus and to ascertain its phylogenetic placement among the other perennial genera of Apiaceae (Umbelliferae) subfamily Apioideae endemic to western North America. To elucidate patterns in the evolution of specific fruit characters and to evaluate their utility in circumscribing genera unambiguously, additional evidence was procured from cross-sections of mature fruits and the results of cladistic analysis of 25 morphological characters. Analyses of the partitioned data sets resulted in weakly supported and largely unresolved phylogenetic hypotheses, possibly due to the rapid radiation of the group, whereas the combined analysis of all molecular evidence resulted in a well-resolved phylogeny with higher bootstrap support. The traditionally used fruit characters of wing shape and compo...
