Papers by Michelle L Hart
Nature Communications, 2014
Grana, 1994
... Regression analysis of the Gnmineae and Urticcl pollen concentrations for 24 hours have been ... more ... Regression analysis of the Gnmineae and Urticcl pollen concentrations for 24 hours have been used to determine relationships between pollen ... Six different weather parameters were used: mean temperature, rainfall, relative humidity, wind speed and direction, and ...
... INTRODUCTION The hybrid between F. japonica var. japonica and F. sacha-linensis - F. x bohemi... more ... INTRODUCTION The hybrid between F. japonica var. japonica and F. sacha-linensis - F. x bohemica (Chrtek & Chrkova) J. Bailey is, however, more widespread (Bailey et aI., 1996). In Glasgow all three of these taxa (F. japonica var. ...
Watsonia, 2000
... Watsonia 17: 163-164. Bailey, JP (1990). Breeding behaviour and seed production in alien Gian... more ... Watsonia 17: 163-164. Bailey, JP (1990). Breeding behaviour and seed production in alien Giant Knotweeds in the British Isles, in Anon., ed. The biology of invasive plants; a BES industrial ecology group symposium, pp. 110-130. Richards, Moorehead and Laing, Ruthin. ...
Renealmia L.f. (Zingiberaceae) is one of the few tropical plant genera with numerous species in b... more Renealmia L.f. (Zingiberaceae) is one of the few tropical plant genera with numerous species in both Africa and South America but not in Asia. Based on phylogenetic analysis of nuclear ribosomal internal transcribed spacer (ITS) and chloroplast trnL-F DNA, Renealmia is shown to be monophyletic with high branch support. Low sequence divergence found in the two genome regions (ITS: 0-2.4%; trnL-F: 0-1.9%) suggests recent diversification within the genus. Molecular divergence age estimates give further support to the recent origin of the genus and show that Renealmia has attained its amphi-Atlantic distribution by an oceanic long-distance dispersal event from Africa to South America during the Miocene or Pliocene (15.8-2.7 My ago). Some support is found for the hypothesis that speciation in neotropical Renealmia was influenced by the Andean orogeny. Speciation has been approximately simultaneous on both sides of the Atlantic, but increased taxon sampling is required to compare the speciation rates between the New World and Old World tropics. (T.E. Särkinen). www.elsevier.com/locate/ympev Molecular Phylogenetics and Evolution 44 (2007) 968-980 R. concinna (2) Panama R. helenae Panama R. concinna (1) Costa Rica R. thyrsoidea (2) Peru R. lucida Panama R. cernua (1) Costa Rica R. pyramidalis Guadeloupe R. alpinia (7) Ecuador R. breviscapa (2) Ecuador R. breviscapa (1) Brazil R. cernua (2) Panama R. pluriplicata Costa Rica R. foliifera Panama R. congesta Costa Rica R. aromatica (3) Venezuela R. aromatica (1) DR R. monosperma Surinam R. alpinia (1) Brazil R. aromatica (2) Peru R. alpinia (7) Ecuador R. dermatopetala Brazil R. alpinia (6) Costa Rica R. alpinia (4) Bolivia R. alpinia (3) Brazil R. alpinia (2) Surinam R. alpinia (5) Costa
Molecular Ecology Resources, 2012
DNA barcoding of a group of European liverwort species from the genus Herbertus was undertaken us... more DNA barcoding of a group of European liverwort species from the genus Herbertus was undertaken using three plastid (matK, rbcL and trnH-psbA) and one nuclear (ITS) marker. The DNA barcode data were effective in discriminating among the sampled species of Herbertus and contributed towards the detection of a previously overlooked European Herbertus species, described here as H. norenus sp. nov. This species shows clear-cut differences in DNA sequence for multiple barcode regions and is also morphologically distinct. The DNA barcode data were also useful in clarifying taxonomic relationships of the European species with some species from Asia and North America. In terms of the discriminatory power of the different barcode markers, ITS was the most informative region, followed closely by matK. All species were distinguishable by ITS alone, rbcL + matK and various other multimarker combinations.
Heredity, 2004
Spiranthes romanzoffiana Cham. is restricted in Europe to the British Isles, where it is recognis... more Spiranthes romanzoffiana Cham. is restricted in Europe to the British Isles, where it is recognised as a conservation priority species due to frequent extirpation of populations along with no evidence of seed set; vegetative reproduction has been invoked as the sole means of perpetuation and dispersal. To investigate the reproductive ecology of this species, 17 populations have been sampled for chloroplast microsatellites and amplified fragment length polymorphisms (AFLPs). These markers revealed a previously unsuspected genetic-geographic split in the species, which correlates with differences in patterns of within-population variation. Northern populations were fixed for one chloroplast haplotype but showed high levels of AFLP genotypic diversity consistent with sexual reproduction (proportion of genotypes distinguishable, P D ¼ 0.98). More southerly populations showed fixed differences from the northern populations in their chloroplast haplotype and for 10 AFLP markers. They harboured only 12 unique multilocus genotypes among 113 individuals from six populations (P D ¼ 0.11). These genotypes differed mostly by single bands, and none by more than 4/138 loci, with identical multilocus genotypes occurring in widely separated populations. This uniformity in southern populations is consistent with agamospermous or autogamous reproduction, and/or an extreme population bottleneck. Finally, the observed patterns of population differentiation in S. romanzoffiana are compared with other studies of orchids, revealing a wide range of values that belie recent contrasting published generalisations that claim that orchids show either higher, or lower, levels of population differentiation than other plant families.
The Elms, 2000
1 The European Elms: Molecular Markers, Population Genetics, and Biosystematics Peter M. Hollings... more 1 The European Elms: Molecular Markers, Population Genetics, and Biosystematics Peter M. Hollingsworth, Michelle L. Hollingsworth, and Max Coleman ... The species appears most frequently on alluvial soils in the Trent and Witham floodplains (Melville, 1940), and it was an ...
Botanical Journal of the Linnean Society, 2000
The taxonomy of the British elms is notoriously complicated and a satisfactory consensus classifi... more The taxonomy of the British elms is notoriously complicated and a satisfactory consensus classification remains elusive. This taxonomic complexity appears to be attributable to the reproductive biology of the species. Ulmus glabra Huds. reproduces sexually and its taxonomic status is widely (albeit not universally) accepted. In contrast, the suckering elms of the U. minor complex (U. minor Mill. emend. Richens sensu latissimo) rarely reproduce by seed in Britain. Instead they perpetuate predominantly by vegetative reproduction; arguments regarding their taxonomy are legion. We have used molecular markers (RAPDs) to investigate the amounts and partitioning of clonal diversity and taxon inter-relationships in the British elms, focusing on a particularly enigmatic suckering elm, U. plotii Druce. Our molecular data suggest that all samples of U. plotii that precisely match the type description are ramets of a single genet, the distribution of which is attributable to human planting. Morphologically similar samples, which have many but not all of the U. plotii diagnostic characters, do not cluster with U. plotii when the RAPD data are analysed using principal coordinates analysis (PCO). Instead, they are scattered on the PCO plots throughout the broader range of variability of the U. minor complex. The implications of these results for the taxonomy of the British elms are discussed, and the need to combine knowledge of population structure with taxonomic pragmatism is emphasized.
Plant Systematics and Evolution, 2002
The phylogenetic position of Parasitaxus (Podocarpaceae) has been inferred from a cladistic analy... more The phylogenetic position of Parasitaxus (Podocarpaceae) has been inferred from a cladistic analysis of molecular characters from chloroplast and nuclear genomes including all genera of Podocarpaceae. In all 24 most parsimonious trees, based on combined datasets, Phyllocladus resided outside Podocarpaceae s. str. while Lepidothamnus was basal to the latter. Most other genera were arranged in two major clades. The evidence confirms previous studies, which have suggested a relationship between Lagarostrobos, Manoao and Parasitaxus. Parasitaxus is not directly related to its host Falcatifolium taxoides. Instead it appears to be most closely related to Manoao and Lagarostrobos. No other members of this group now occur on New Caledonia. However, if the evolution of Parasitaxus were autochthonous, a free-living member of this group must once have occurred there. An accelerated evolutionary rate of the chloroplast sequence analysed was suggested, indicating that the plant behaves like a holoparasite.
Botanical Journal of the Linnean Society, 2007
Botanical Journal of the Linnean Society, 1999
American Journal of Botany, 2009
Molecular Ecology, 1998
Throughout the world, many plant communities contain a large proportion of introduced species. In... more Throughout the world, many plant communities contain a large proportion of introduced species. In a recent account of the flora of the British Isles, Stace (1997) judged 1391 out of the 2963 species described to be alien. Many of these introduced species have become ...
Proceedings of the National Academy of Sciences, 2009
DNA barcoding involves sequencing a standard region of DNA as a tool for species identification. ... more DNA barcoding involves sequencing a standard region of DNA as a tool for species identification. However, there has been no agreement on which region(s) should be used for barcoding land plants. To provide a community recommendation on a standard plant barcode, we have compared the performance of 7 leading candidate plastid DNA regions (atpF-atpH spacer, matK gene, rbcL gene, rpoB gene, rpoC1 gene, psbK-psbI spacer, and trnH-psbA spacer). Based on assessments of recoverability, sequence quality, and levels of species discrimination, we recommend the 2-locus combination of rbcL؉matK as the plant barcode. This core 2-locus barcode will provide a universal framework for the routine use of DNA sequence data to identify specimens and contribute toward the discovery of overlooked species of land plants.
Molecular Ecology, 2002
The genus Epipactis contains a problematical complex of autogamous taxa among which species limit... more The genus Epipactis contains a problematical complex of autogamous taxa among which species limits are difficult to define. Different authors have treated these plants in different ways, some recognizing the different taxa as distinct species, others considering them as minor intraspecific variants. These contrasting treatments have a direct impact on the conservation resources and status such plants command; 'endemic orchid species' are perceived as having high conservation value, 'localized minor variants' are not. We used allozyme and chloroplast restriction fragment length polymorphism (RFLP) and sequencing analyses to investigate patterns of population genetic structure underlying the taxonomic complexity in this group. Populations of E. dunensis , E. leptochila and E. muelleri were homozygous and uniform for all loci studied here. There were, however, fixed genetic differences among these taxa. Comparisons with published data from the putative progenitor species for the autogamous taxa (the widespread, allogamous E. helleborine ) suggest iterative origins of autogamy, rather than the self-pollinating taxa all being merely mutational variants of a single autogamous lineage.
Biological Conservation, 2005
ABSTRACT The enormous losses suffered by the European elms during recent Dutch elm disease outbre... more ABSTRACT The enormous losses suffered by the European elms during recent Dutch elm disease outbreaks led to concern over the conservation of elm genetic resources, and the subsequent establishment of a series of ex situ collections. However, as ex situ collections are inevitably finite in size, some consideration needs to be given to selecting which samples to include in them. To contribute towards this process for European ex situ elm collections we have undertaken genetic studies on a Europe-wide sample of 535 individuals. A major aim has been to use genetic markers to clarify the identification of samples to ensure that the ex situ collections contain a representative spread of taxonomic diversity. This is important given the paucity of mature elms in the landscape due to Dutch elm disease. The lack of mature material (critical for identification) compounds identification problems in what was already a taxonomically difficult group. Our data (derived from random amplified polymorphic DNA and inter-simple sequence repeats) have provided a useful supplement to morphology in undertaking such sample identifications. The molecular data served to highlight mis-identified samples and led to extensive revisions of sample identities within individual countries. Our results were less useful in detecting regional intra-specific genetic structure, and do not provide sufficient information for prioritising within-species sample selections.
Nature Communications, 2014
Unraveling the macroevolutionary history of bryophytes, which arose soon after the origin of land... more Unraveling the macroevolutionary history of bryophytes, which arose soon after the origin of land plants but exhibit substantially lower species richness than the more recently derived angiosperms, has been challenged by the scarce fossil record. Here we demonstrate that overall estimates of net species diversification are approximately half those reported in ferns and B30% those described for angiosperms. Nevertheless, statistical rate analyses on timecalibrated large-scale phylogenies reveal that mosses and liverworts underwent bursts of diversification since the mid-Mesozoic. The diversification rates further increase in specific lineages towards the Cenozoic to reach, in the most recently derived lineages, values that are comparable to those reported in angiosperms. This suggests that low diversification rates do not fully account for current patterns of bryophyte species richness, and we hypothesize that, as in gymnosperms, the low extant bryophyte species richness also results from massive extinctions.
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Papers by Michelle L Hart