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1
Mwafongo, Elizabeth. "Morphological study of Schizaea Pectinata (L.) Sw. (Schizaeaceae)." Bachelor's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/23941.
Full textAbstract:
Morphometrics was used to study variation in Schizeae pectinata as previous study showed that material originating from the summer rainfall area of South Africa differ in several aspects from that originating from the winter rainfall area. The plant has a simple structure and consequently spore, stoma and sporangia sizes, as well as the number per lamina was studied to determine if the species can be subdivided into two groups, e summer and e winter rainfall group, as was previously hypothesised. Univariate and bivariate methods were used to display the extent of variation within the species. Univariate analysis reflect variability of spore and stomata size, and the number of pinna pairs per lamina. Statistical analyses showed that interpopulation variation for these characters are often highly significant. Phonetic methods were used in the analyses of the data set and shows continuous variation in this species. This continuous variation in Schizaea pectinata could be linked to a phenotypic response to environmental differences between the two regions.
2
Luna, Castro Javier Alejandro. "Systematics, biogeography and studies of floral evolution in Gesneriaceae." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29523.
Full textAbstract:
Understanding the processes that have affected the diversification of herbaceous plants is fundamental to understand how flowering plants evolve, how ecosystems form and to predict the effect of climate change and geological events in plant communities. Aiming to create a strong phylogenetic framework where biogeographic and morphological hypothesis can be tested a higher level dated phylogeny of Gesneriaceae was produced. Gesneriaceae is a good study group as it has variable floral morphology, a broad distribution throughout the tropics and subtropics - represented in all non-arid tropical and subtropical hotspots of biodiversity. There are evident differences between lineages in the numbers of species, and it is comparatively well studied compared with other asterid families. In this study a consolidated taxonomic hypothesis of Gesneriaceae is suggested based on a genus level phylogeny, the ages of the main lineages of the family are presented, the effect of geological events are explored, the geographic origin of lineages are suggested and an insight into the effect of floral morphology on the evolution of the family is given. Limiting the taxonomic scope and focusing on a single family should help us better understand how flowering plants diversify.
3
Bentley, Joanne. "The evolution of the Afrotemperate-endemic genus Macowania (Asteraceae) in the Drakensberg region of South Africa." Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/24852.
Full textAbstract:
The cosmopolitan Asteraceae tribe Gnaphalieae, or paper daisies or everlastings, form a significant component of both the dry and cool temperate floras of southern Africa. Within this tribe exists a small Afrotemperate genus, Macowania, endemic to the grassland biome of South Africa and occurring almost exclusively within the Drakensberg region, apart from two disjunct species in North Africa. The age, relationships and geographic origin of Macowania is investigated in order to provide insight into the factors affecting speciation, especially uplift events, on this small Afrotemperate genus. A well-supported phylogenetic hypothesis based on both nuclear and chloroplast genes suggests that Macowania is sister to a clade corresponding to the Relhania clade s.s., and that these are in turn sister to a clade containing the genera Athrixia and Pentatrichia. Macowania is monophyletic only with the inclusion of the enigmatic monotypic genus Arrowsmithia, resulting in the future synonymy of Macowania with Arrowsmithia. The anomalous species M. pinifolia, previously part of the genus Athrixia, is placed in a polytomy with the Relhania s.s. clade and the remaining species of Macowania and Arrowsmithia. DNA sequence data could not be obtained for several Macowania species, including the taxa from North Africa. The placement of these species within Macowania is confirmed by means of a parsimony analysis of morphological characters against a molecular backbone constraint tree. One species, M. tenuifolia, is well-supported in two different placements within Macowania by chloroplast and nuclear DNA sequence data. The best position of this species is inferred by incongruence decomposition analysis and morphological affinities. Bayesian relaxed clock methods and ancestral area reconstruction using maximum likelihood and squared change parsimony estimate the age and ancestral area of the genus, and determine the timing and route of colonisation of the Drakensberg. Diversification within Macowania is consistent in timing with the uplift events during the Miocene and Pliocene that resulted in significant vertical movement in eastern South Africa, suggesting that colonisation of the high-elevation Drakensberg grassland by Macowania was promoted by uplift. The topographic heterogeneity and increased river action resulting from the uplift may also have promoted evolution into new habitats and potentially mediated the movement of the ancestor of Macowania into the Drakensberg region via riparian habitats.
4
Thomas, Janet Clare. "The structure of the perennial growth of Disa uniflora Berg. (Orchidaceae)." Bachelor's thesis, University of Cape Town, 1990. http://hdl.handle.net/11427/26497.
Full textAbstract:
The perennation of orchids is poorly understood, in particular that of the Orchidoidae. The understanding of perennation in the Orchidoidae is important because the root-stem tuberoid is used as the one character defining the Orchidoidae as a monophyletic group. The root-stem tuberoid has never been examined for variation before. This project focuses on perennial growth in the Diseae in order to study the structure and function of the root stem tuberoid in relation to other organs and to contribute to the understanding of Orchidoid phylogeny.
5
Verboom, George Anthony. "An investigation of character variation in Chaetobromus Nees (Danthonieae: Poaceae) in relation to taxonomic and ecological pattern." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/18333.
Full textAbstract:
Character variation in Chaetobromus, a genus of palatable grasses endemic to the arid western areas of southern Africa, was used to derive a classification reflecting taxonomic and ecological pattern. The present study differs from earlier biosystematic investigations by its much more intensive approach to sampling, with 75 anatomical, morphological and cytological characters and 169 individual samples being used. The use of larger population samples permitted quantification of variation within populations, in addition to that among populations and groups. Phenetic methods revealed the existence of three groups, approximating three formerly described taxa and reflecting divergent ecological strategies in Chaetobromus. A lack of diagnostic field characters argues against their recognition at species level, and Chaetobromus Nees is here described as monotypic, the type species, C. involucratus (Schrad.) Nees, comprising three subspecies C. involucratus subsp. involucratus, C. involucratus subsp. villosus Verboom and C. involucratus subsp. dregeanus (Nees) Verboom. There is overlap among subspecies in most characters although many showed significant mean differences. Within subspecies, character variation appears to be homogeneously distributed with respect to population boundaries suggesting that these are likely to have little impact on sampling. An investigation testing the effect of sample strategy on variation capture and taxonomic group detection suggests that a sample of 10-15 specimens is likely to account for most variation present. Phylogenetically, Chaetobromus is included in the tribe Danthonieae, and, on morphological evidence, is probably basal to a clade containing Pentaschistis, Pentameris and Pseudopentameris. The genus appears to occupy a niche unique among the African danthonioids, favouring lime-rich, basic soils and a strongly-seasonal winter-rainfall regime with arid summers. Ecological differences among the subspecies are reflected in differences in growth form and vegetative and reproductive phenologies. The niche requirements of Chaetobromus may be adequately specific to explain the patchy distribution of the genus. Bibliography: pages 119-131.
6
Donnell, Aliya A. "A Systematic Revision of Bakeridesia Hochr. (Malvaceae)." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1345563427.
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7
Sweeney, Patrick Wayne. "Systematics and floral evolution in the plant genus Garcinia (Clusiaceae) /." View online, 2007. https://apps.umsl.edu/webapps/weboffice/ETD/query.cfm?id=r2641.
Full textAbstract:
Thesis (Ph. D.)--University of Missouri--St. Louis, 2007.Includes bibliographical references. Also available via the Internet: https://apps.umsl.edu/webapps/weboffice/ETD/query.cfm?id=r2641 (viewed May 19, 2009).
8
Maguire, Victoria. "Immunogold labelling of TIP proteins in the resurrection plant Craterostigma plantagineum." Thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/26509.
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9
Zaheer, Khalid. "Virulence and biochemical systematics of potato cyst-nematodes (PCN)." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334687.
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10
McGrath, Kate. "Phylogeography and population genetics of two forest endemic mosses in the Cape Floristic Region." Bachelor's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/26502.
Full textAbstract:
Different histories for forests in Southern Africa have been hypothesized from vegetation biogeography and pollen analysis. However, the history of forests is still controversial. Phylogeography uses gene genealogies to infer history of distributions. Two forest endemic moss species were sampled: Leptodon smithii; and Neckera valentiniana. Two gene regions were used, trnLF (chloroplast genome) and ITS1 (nuclear genome). Neckera valentiniana showed no variation from the populations sampled. Results from Leptodon smithii based on the trn and ITS region suggest that forests once were widespread, but then became fragmented. Dispersal corridors still exist between Southern Cape populations and Western Cape populations.
11
Franck, Alan R. "Systematics of Harrisia (Cactaceae)." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4044.
Full textAbstract:
The genus Harrisia Britton (Cactaceae) comprises species of columnar cacti that are united by a unique seed morphology. The species range in form from prostrate shrubs to large trees and are native to South America and the Caribbean region. Harrisia is placed in an unresolved position within subtribe Trichocereinae of tribe Cereeae of subfamily Cactoideae. Relationships among the species within Harrisia are also poorly understood. In this study, several species of Harrisia were sequenced for as many as seven different regions of nuclear and plastid DNA. Species in the Caribbean were also examined with amplified fragment length polymorphisms. The morphology of Harrisia was characterized from herbarium specimens, live plants, and original descriptions. A biogeographic scenario was extrapolated from the molecular and morphological data. The flower morphology suggests a relationship between Harrisia and some species of Echinopsis s. l. However, DNA sequence analyses in this study do not clearly resolve generic relationships with Harrisia. Molecular and morphological data support recognition of two subgenera, four sections, and two series within Harrisia. It is proposed that Harrisia originated in the west-central Andes, ~3.5-6.5 Ma ago. Subgenus Eriocereus is composed of the species in the east Andes of Bolivia and the nearby species radiation in the Gran Chaco. Subgenus Harrisia originated by an early dispersal event into Brazil with subsequent dispersal into the Caribbean. In the last 500 Ka, Harrisia, colonized west Cuba and further diversified into other areas of the Caribbean. Harrisia is revised to contain 18 species.
12
Wright, Bethany Ann. "Systematic studies in the genus Phlox (polemoniaceae): cytotypic variation in Phlox nana nutt. and utility of a low copy nuclear gene region (IDHB) for phylogeny development." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18242.
Full textAbstract:
Master of ScienceDepartment of Biology
Carolyn J. Ferguson
The genus Phlox L. presents intriguing opportunities for systematics research, and P. nana is of particular interest. Phlox nana occurs chiefly in mountains of the Chihuahuan desert to northern New Mexico, and it exhibits much morphological variation across its range. Historically, this taxon has been recognized as a single species (sometimes with infraspecific taxa), or as several species. Perhaps most interesting, variation in ploidy level (cytotypic variation) has been evidenced for P. nana. This research employed flow cytometry methods in conjunction with chromosome counts to document patterns of cytotypic variation. Intensive fieldwork in Arizona, New Mexico and Texas enabled excellent sampling, and evaluation of ploidy level for 76 populations was achieved. Diploid and tetraploid chromosome counts were made (four diploid counts; five tetraploid counts), and flow cytometry was conducted on all populations, providing evidence for diploid, tetraploid and hexaploid populations. Polyploids were found to occur in many geographical areas, and in some regions, diploids and polyploids occur in close geographical proximity (e.g., within both the Davis Mountains and the Chisos Mountains of west Texas). Genome size data are presented (with discussion of unusual populations), and geographic patterns of cytotypic variation are presented and discussed. Patterns are also briefly considered with respect to morphology and taxonomy: cytotypic variation does not readily align with historical recognition of taxonomic variation, and this work sets the stage for ongoing, detailed morphometric study. Research on particular species of Phlox benefits from an understanding of a broad phylogenetic context, and low copy nuclear DNA regions are an important resource for phylogeny development. This research further evaluated part of the NADP-dependent isocitrate dehydrogenase gene (idhB) for its usefulness in inferring relationships in Phlox. Samples were PCR amplified for idhB and cloned, and resulting sequences were added to a larger set of idhB sequence data previously developed in the lab. A total of 163 samples were included, and Bayesian Inference and Maximum Parsimony analyses were conducted for complete data sets. Phylogenetic findings are discussed in light of previous work based on chloroplast and high copy nuclear DNA regions, and challenges and utility of using idhB are discussed.
13
Guo, Yuelong. "Molecular Systematics of Philadelphus and Molecular Evolution of LFY in the Core Eudicots." NCSU, 2010. http://www.lib.ncsu.edu/theses/available/etd-03262010-121851/.
Full textAbstract:
Phylogenetic analysis is a powerful tool for elucidate evolutionary relationships of organisms and genes and for testing taxonomic and evolutionary hypotheses. I conducted phylogenetic analyses of DNA sequences from five gene regions to evaluate the classification scheme of Philadelphus and used phylogenetic analysis to provide a framework for examining molecular evolution of the LFY gene in plants. Results from my study suggested that Philadelphus is a paraphyletic group with the single species genus Carpenteria nested within. Three evolutionary distinct clades were identified in this large Carpenteria-Philadelphus complex, the subgenus Deutzoides clade, the genus Carpenteria clade, and the remaining Core-Philadelphus clade, each merits the recognition of a genus. Our results mostly agreed with the most recent treatment of genus Philadelphus on the placement of Deutzoides, with the exception of P. hirsutus. However, our result does not support the classification scheme proposed for the rest Philadelphus species. Biogeographic analysis using the Statistical Bayes-DIVA method (S-DIVA) and divergence time dating with the BEAST method resolved the origin of Philadelphus s. l. in southwestern North America in the Oligocene. Several intercontinental migrations from North America to Asia and to Europe occurred at the different times of the later Tertiary to reach a worldwide distribution of the genus. For the molecular evolution study of LFY gene, our results revealed that the evolution of LFY was under strong functional constraint, with the C domain under the strongest selection force and the intervening domain being the most relaxed. Our study also showed that the detection of positive selection using the Branch Site Model was robust to taxon sampling density, but sensitive to sequence length and alignment ambiguity. Our analyses under various conditions consistently detected positive selection in Fabaceae, where FLO/LFY evolved a role of the KNOX1 gene function in regulating compound leaf development. Under the best alignment, we detected adaptive selection at several sites in Asterales, Brassicaceae, and Fabaceae where gene duplication and/or novel function of LFY have been reported.
14
Lee, Sangmi. "SYSTEMATICS OF HOLARCTIC TELEIODINI (LEPIDOPTERA: GELECHIIDAE)." MSSTATE, 2007. http://sun.library.msstate.edu/ETD-db/theses/available/etd-05232007-092441/.
Full textAbstract:
Phylogenetic relationships of 25 genera of Holarctic Teleiodini (Gelechiidae) are postulated based on morphology and molecular characters, including CO?I, CO?II, and 28S genes. The phylogenetic analysis of the morphology matrix yielded six equal most parsimonious trees (length 329 steps, CI = 0.38, RI = 0.53) and a strict consensus tree (length 342 steps, CI = 0.36, RI = 0.50) with two polytomies and two trichotomies. The phylogenetic analysis of the combined morphology matrix and the CO?I + CO?II + 28S matrix yielded two equally most parsimonious trees (length 1184 steps, CI = 0.50, RI = 0.41) and a strict consensus tree (length 1187 steps, CI = 0.50, RI = 0.40) that reinforced results from the morphological analysis and resolved the two polytomies and one of the two trichotomies present in the morphology consensus tree. Teleiodini are defined as a monophyletic clade with a Bremer support value greater than 5 in the consensus tree based on morphology and molecular data. Twenty?three clades of genera are defined with Bremer support values provided. An analyses of larval host plant preferences based on the consensus tree for combined data indicates derivation of feeding on woody hosts from genera feeding on herbaceous hosts and a single origin of feeding on coniferous hosts. An area cladogram indicates five independent origins of Nearctic genera from Holarctic ancestors and one origin from a Palearctic genus. The review of genera includes descriptions of imagos, genitalia, larvae, and pupae with illustrations of selected species. A new genus and a new species from Alabama and Mississippi, United States are described with illustrations of imago, wing venation, and male and female genitalia.
15
Speer, William D. "Systematics of Eastern North American Bracken Fern." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36715.
Full textAbstract:
The cosmopolitan Pteridium aquilinum (L.)
Kuhn is widespread throughout eastern
North American, where it is represented
primarily by Tryon's (1941) var. latiusculum
(Desv.) Underw. and var. pseudocaudatum
(Clute) Heller. The taxonomy of Pteridium is
controversial. Fourteen isozyme loci and 12
morphological characters were used to
assess the taxonomic relationship of these
two varieties. Isozyme data indicated a high
mean genetic identity (I = 0.976) between
eleven bracken populations. Strong patterns
of geographic variation for isozyme allele
frequencies were also observed. The isozyme
results did not separate the two taxa.
Numerical analysis of the morphology
distinguished the two taxa when the
qualitative characters were used alone or in
conjunction with some of the quantitative
traits. All qualitative characters differed
significantly between the two taxa. No
perceptible geographic pattern of variation
was observed. Morphological distinctiveness
was maintained even in those localities where
both taxa were present, with few or no
intermediates being found. Isozyme evidence
suggestive of gene flow between the two
varieties was found at Greensboro, NC,
where the two morphotypes were easily
recognizable. The isozyme evidence strongly
indicates conspecificity, while the
morphological evidence supports their status
at the varietal level.Master of Science
16
Islam, Shah Mohammad Naimul. "Systematics, ecology and plant associations of Australian species of the genus metarhizium." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/117674/2/Shah%20Mohammad%20Naimul_Islam_Thesis.pdf.
Full textAbstract:
Fungi of the genus Metarhizium (Family:Clavicipitaceae, Order: Hypocreales) can be both pathogens of insects and form mutualistic relationship with plants. This research collected and described Metarhizium isolates from agricultural crops, grasslands and forests soils Queensland, Australia and identified crop, soil factors and agricultural management that may affect the distribution of the species. It identified two new taxa of the genus and identified the presence of several species known to occur internationally. There were specific associations of taxa with crop and ecotype. The two new Australian taxa also colonized the roots of maize, a monocot, in contrast to other taxa which typically favor eudicots (legumes). It also identified the potential role of the plant hormone strigolactone in fungal colonization of the plant root. The work identified the potential to select fungal taxa in order to improve crop production through application of these fungi as root inocula.
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Armstrong, Kate. "Systematics and biogeography of the pantropical genus Manilkara Adans (Sapotaceae)." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/4871.
Full textAbstract:
Mechanisms for the generation of biodiversity in species-rich biomes such as rain forests remain unclear. Molecular phylogenies using DNA sequence data, calibrated with a temporal dimension offer a means of addressing this question, enabling the testing of different hypotheses on biogeographic histories and causes of diversification. Manilkara is a genus of trees in the Sapotaceae consisting of ~79 species distributed throughout the tropics (30 South and Central American, 35 African and 14 Southeast Asian). This species diversity in all major tropical regions of the globe makes it an ideal candidate for in-depth biogeographic studies. Maximum parsimony and Bayesian analyses of nuclear (ITS) and chloroplast (rpl32-trnL, rps16-trnK and trnS-trnFM) sequences were used to reconstruct a species level phylogeny of Manilkara and related genera in the tribe Mimusopeae. Manilkara, as currently defined, is not monophyletic due to the placement of three Asian taxa (M. fasciculata, M. dissecta and M. udoido), which are more closely related to the Madagascan genera Labourdonnaisia and Faucherea than to Manilkara s.s. and need to be re-circumscribed in a new genus. Letestua is nested in Manilkara and the genera Faucherea and Labourdonnaisia are not monophyletic. Nuclear and chloroplast datasets were mostly congruent, however, three instances of hard incongruence were demonstrated, suggesting chloroplast capture events. Bayesian analyses of ITS sequences using a relaxed molecular clock calibrated with fossils, focused on testing biogeographical hypotheses on the origin of Manilkara’s pantropical disjunct distribution and spatio-temporal diversification patterns on each continent. Mimusopeae, originated during the Eocene ~46-57 Ma and fossil evidence supports its existence in the boreotopical region of the northern hemisphere during this time. This suggests that the tribe may have evolved there and found refuge in Africa when Oligocene climatic cooling made higher latitudes uninhabitable for megathermal taxa. The subtribe Manilkarinae was resolved as ~42-36 Myo. These ages fall on the Eocene-Oligocene boundary and the crown node age coincides with the onset of Oligocene cooling and the closing of the boreotropical route. The genus Manilkara is estimated to have evolved ~36-33 Ma. The current distribution of the genus could not, therefore, have been the result of Gondwanan vicariance or migration through the boreotropics, but results instead support long distance dispersal as an important factor influencing the distribution of the group. Resolution along the backbone of the phylogeny is weak and the area of origin is, therefore, difficult to determine. However, all sister taxa to Manilkara are African and this suggests that the most likely explanation is an African origin for the genus with subsequent inter-continental dispersal during the Miocene. Manilkara spread from Africa to the Neotropics and Asia via at least three separate long distance dispersal events. A single lineage dispersed to the Neotropics ~27-21 Ma and spread across the Isthmus of Panama before its closure. Another lineage dispersed to Southeast Asia ~30-25 Ma from mainland Africa and subsequently diversified throughout the region. A third dispersal from Madagascar to the Sahul Shelf, occurred ~31-16 Ma in the M. fasciculata/dissecta/udoido lineage. In South America, diversification is consistent with both aridification and the rearrangement of drainage patterns in the Amazon basin as a result of Andean orogeny. The Atlantic coastal forest clade and the Amazonian clade of Manilkara split from one another ~14 Ma, at approximately the same time as the dry biomes of the Cerrado and Caatinga were forming between them. In Africa diversification coincides with Tertiary cycles of aridification and uplift of the east African plateaux. In Southeast Asia Wallace’s Line did not affect the dispersal of Manilkara. Instead, the limiting factor was the appearance of land in New Guinea ~10 Ma, which coincides with the dispersal and establishment of new taxa east of Wallace’s Line. Spatio-temporal patterns of diversification in Manilkara were compared to those of 34 other wet tropical genera which have intercontinental disjunctions. Ages of disjunctions ranged from the Eocene to the Pliocene, indicating that compilation of the tropical rain forest biome is a dynamic process which has been occurring throughout the Tertiary. Recent migration via long distance dispersal is a significant phenomenon in biome construction. Geo-climatic events have also been shown to be important drivers of diversification in all continental regions.
18
Victor, Janine Elizabeth. "Strategies for the development of plant systematics in a floristically diverse region." Thesis, University of Pretoria, 2015. http://hdl.handle.net/2263/53564.
Full textAbstract:
South Africa is one of the most biologically diverse countries in the world, and harbours one
of the richest floras. Vast areas of the country remain under-collected, and a large proportion
of species are taxonomically problematic and under-represented in herbarium collections.
These factors hinder management of biodiversity. The main intention of this study was to
develop a strategy for plant taxonomic research that would meet the needs of end users, and
make efficient use of scarce human and financial resources in South Africa.
The development of plant taxonomy in South Africa from 1600 to 2014 is reviewed,
with emphasis on the main driving factors that have influenced the research direction,
techniques used, and choice of taxonomic research topic. At present the predominant culture
of taxonomy is directed towards electronic dissemination of taxonomic information, leading
to increased accessibility and connectivity.
An assessment of plant taxonomic capacity in South Africa is provided. From an
analysis of the existing gaps in taxonomic information, current research trends, and existing
resources, it is apparent that there is a critical shortage of human capacity in South Africa to
conduct plant taxonomic research for the benefit of biodiversity and society.
An objective method of prioritising taxa in urgent need of taxonomic research was
developed and can potentially be used for all organisms and be equally applicable to other parts of the world. This methodology informed the development of a Strategy for plant
taxonomic research in South Africa 2015 2020. Three research programmes are proposed to
focus on the main gaps in taxonomic knowledge, and a plant collecting programme is
suggested to improve foundational biodiversity data. The maintenance of high quality
standards for information contained in taxonomic databases is crucial, hence
recommendations are made for addressing data quality.
Since implementation of the Strategy at SANBI in 2011, progress has been
satisfactory. It is anticipated that by 2020, South Africa will have a centralised online
electronic resource for plant taxonomic information; the number of genera in urgent need of
revision will have halved; and taxonomically problematic taxa reduced by 20%. In this way
strategic planning benefits both taxonomy and end users.Thesis (PhD)--University of Pretoria, 2015.
Plant Science
PhD
Unrestricted
19
Flicker, Benjamin J. "The Systematics of Afrohybanthus Flicker (Violaceae), A New Segregate Genus From The Old World Tropics." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1398875625.
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Muhl, Sara. "The patch-scale distribution pattern of Stipa capensis and its affect on annual plant diversity and growth." Thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/23933.
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Rai, Hardeep Singh. "Molecular phylogenetic studies of the vascular plants." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/3889.
Full textAbstract:
To investigate vascular-plant phylogeny at deep levels of relationship, I collected and analyzed a large set of plastid-DNA data comprising multiple protein-coding genes and associated noncoding regions. I addressed questions relating to overall tracheophyte phylogeny, including relationships among the five living lineages of seed plants, and within two of the largest living gymnosperm clades (conifers and cycads). I also examined relationships within and among the major lineages of monilophytes (ferns and relatives), including their relationship to the remaining vascular plants. Overall, I recovered three well-supported lineages of vascular plants: lycophytes, monilophytes, and seed plants. I inferred strong support for most of the phylogenetic backbones of cycads and conifers. My results suggest that the cycad family Stangeriaceae (Stangeria and Bowenia) is not monophyletic, and that Stangeria is instead more closely related to Zamia and Ceratozamia. Within the conifers, I found Pinaceae to be the sister-group of all other conifers, and I argue that two conifer genera, Cephalotaxus and Phyllocladus (often treated as monogeneric families) should be recognized under Taxaceae and Podocarpaceae, respectively. Systematic error likely affects inference of the placement of Gnetales within seed-plant phylogeny. As a result, the question of the relationships among the five living seed-plant groups still remains largely unresolved, even though removal of the most rapidly evolving characters appears to reduce systematic error. Phylogenetic analyses that included these rapidly evolving characters often led to the misinference of the “Gnetales-sister” hypothesis (Gnetales as the sister-group of all other seed plants), especially when maximum parsimony was the inference method. Filtering of rapidly evolving characters had little effect on inference of higher-order relationships within conifers and monilophytes, and generally resulted in reduced support for backbone relationships. Within the monilophytes, I found strong support for the majority of relationships along the backbone. These were generally congruent with other recent studies. Equisetaceae and Marattiaceae may be, respectively, the sister-groups of the remaining monilophytes and of the leptosporangiate ferns, but relationships among the major monilophyte lineages are sensitive to the outgroups used, and to long branches in lycophytes.
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Othman, Ahmad Sofiman. "Molecular systematics of the tropical aquatic plant genus, 'Cryptocoryne' Fischer ex Wydler (Araceae)." Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/11044.
Full textAbstract:
Cryptocoryne is an aquatic plant genus occurring in tropical Asia. A number of species within the genus are widely used as foliage plants in tropical fish aquaria. The taxonomy and systematics of the genus have been based in the past on morphological characteristics, geographical distribution and chromosome number. The aim of this research was to construct a phylogeny for the genus based on molecular variation and to establish relationships among species in areas of different geographical origin and of different chromosome base number. A phylogeny constructed from sequence variation of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA, separated the genus into three distinct clades reflecting a strong geographical pattern. One clade consisted of species from mainland Asia, another was comprised of species from Sri Lanka while the third clade consisted of species from Malesia. However, these clades did not reflect rigidly the geographical origin of areas in which the genus is distributed. The ITS phylogeny also indicated that species with a base chromosome number of x=14 are derived from x=18 stock, and that x=l1 has arisen twice in the course of the evolution of the genus. The origin of other chromosome base numbers, i.e. x=15 and x=17, was not clearly resolved. A phylogeny based on chloroplast (cp) DNA sequence variation was similar in topology to that of the ITS phylogeny although resolution of species relationships was not so good. Phenograms produced from RAPD variation gave a better resolution of affinities among closely related Cryptocoryne species from Sri Lanka, but differed in overall topology from the phylogenies obtained from ITS and cpDNA sequence variation. Compelling evidence for the origin of the hybrid C. x willisii from C. walkerii and C. parva was obtained from the RAPD analysis, in that C. x willisii exhibited an additive RAPD profile which combined the profiles of its two putative parents. C. x willisii also contained an ITS sequence similar to that of C. walkeri in some accessions examined, and a cpDNA sequence similar to C. walkeri and its close relative C. beckettii.
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Prill, Nadine. "Effects of environmental change on plant performance and plant-herbivore interactions." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:c58761e9-666c-4b7d-a78a-d70de7f253d4.
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Global environmental change fundamentally affects plants and their interactions with other species, and this has profound impacts on communities and ultimately ecosystems. In order to understand the mechanisms involved, we need to elaborate on the combined effects of different global change drivers on multiple levels of plant organization, including the biochemical level (production of defence compounds), the whole organism, the population, and the plant-herbivore interaction level. This thesis investigates (1) the combined effects of factors related to climate change and habitat fragmentation on Brassica nigra and (2) the effects of Zn soil pollution on the heavy metal hyperaccumulator Noccaea caerulescens at these different levels. Common garden and greenhouse experiments with B. nigra applied drought stress and elevated CO2 to examine climate change impacts, while crossing treatments (inbreeding and between-population outbreeding) were used to investigate habitat fragmentation effects. Heterosis was lost under drought stress, and there were several interactive effects of the experimental treatments that varied within and among populations. In a greenhouse experiment with N. caerulescens, plants were grown on soil with different amounts of zinc. Plants had greater herbivore resistance when grown on Zn-amended soil, and invested more in herbivore tolerance when grown on soil without added Zn. In general, the results indicate that factors related to global environmental change have complex and interactive effects on different levels of plant organization. The findings are discussed in terms of their implications for ecology, evolution and conservation.
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Szöke, Tim. "A hierarchical phytosociology of the Greater Zandvlei area." Bachelor's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/24963.
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The Zandvlei Nature Reserve is to be expanded to form the Greater Zandvlei Estuary Nature Reserve and will encorporate a much greater area (250 more hectares). The Greater Zandvlei area was classified by means of Zurich Montpellier (Braun Blanquet) procedures. 60 relevés were used to create a hierarchical phytosociology using TWINSPAN and DCA-ordination analyses. 3 major community types were identified, which were then subdivided to reveal 6 community types important to future management: Moist Grassland/Wetland Disturbed Parkland, Dune Asteraceous Fynbos, Thicket/Shrub Mosaic, Rhus-Euclea Dune Thicket and Homogenous Patches. CCA-ordination indicates that the abiotic soil factors sampled (texture composition, pH, carbon content and visible disturbance) explain very little of the variation between the communities (r²=0.002). This phytosociology is provided as a tool for future research in the area, and it is hoped to assist in future management decisions regarding the newly founded GZENR.
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Muhl, Sara. "Long-term salinity trends in Zandvlei estuary and implications for dominant macroalgae." Bachelor's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/25721.
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Zandvlei is a system that has been highly modified by the urban environment of Cape Town. Salinity is a major driver determining the physical environment of estuaries. The macroalgal community of estuaries forms an important part of the ecology of these systems as primary producers. The salinity of this environment is an important parameter determining the composition, abundance and diversity of these communities. Patterns of salinity fluctuations in the long term (1978-2003) and annually are described in order to establish how communities may vary. Zandvlei is in a Mediterranean climate and salinity was found to vary seasonally and monthly with fluctuations in rainfall. Historical records of macroalgae identified in the estuary were summarized and no record of the Polysiphonia sp., now dominant in the estuary, was found. Dominant macroalgae in the estuary were identified and grown under a range of salinities (0, 1, 5, 10, 20, 29 ppt). Dominant macroalgae included Cladophora sp., Polysiphonia sp. and Enteromorpha prolifera. None of these algae survived at O ppt. In 1 ppt E. prolifera survived but growth was retarded, Polysiphonia sp. survived but did not grow and Cladophora sp. grew successfully at this salinity. All three species have different optimum ranges for growth with E. prolifera preferring higher salinities, Cladophora sp. grew similarly across the range from 1 to 29 ppt and Polysiphonia sp. grew most rapidly at 5 ppt. Depending on the salinity range in the estuary different macroalgae will be dominant. This makes the macroalgae community quite resilient to fluctuating salinities. There should therefore always be estuarine macroalgae present in the estuary provided salinity does not drop below 1 ppt for an extended period. If salinities did drop below 1 ppt there could be an increase in freshwater algae.
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Hempson, Gareth. "An alternative hypothesis for explaining anomalies in the fine scale distribution patterns of Colophospermum mopane : Are shrub and tree forms genetically distinct ?" Bachelor's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/26022.
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Abiotic and top down control hypotheses do not adequately explain the fine scale distribution patterns of shrub and tree Colophospermum mopane (Caesalpinioideae). Genetic distinctiveness between growth forms is investigated as an alternative hypothesis. Tree and shrub C. mopane from the riparian and inland savanna zones were sampled at four sites in the northern Kruger National Park. Molecular DNA sequences were obtained for four plastid and one nuclear region, and the inter simple sequence repeat (ISSR) technique used to fingerprint individuals. Very low levels of sequence divergence were observed. The ISSR technique revealed no genetic structure between plants when grouped by growth form or by habitat in an analysis of molecular variance (AMOV A). Soil profile and xylem pressure potential data also did not explain the distribution of growth forms. A principle component analysis and a discriminant analysis of five leaf and branching characters identified a significant difference in the shape of shrub and tree C. mopane leaves. It is concluded that the C. mopane growth forms are not genetically distinct and that their fine scale distributions may be due to top down controls such as large mammals and fire.
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Hempson, Gareth. "Quantifying Acacia defences : understanding the role of hooks, spines and architecture." Bachelor's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/26121.
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The effectiveness of the structural defences of Acacias vary within and between species as a result of differences in thorn type (hooks versus spines) and branching architecture. This study aims to develop methods for quantifying the effectiveness of defences, thereby allowing for comparisons between individuals and localities. Measurements of a range of thorn and branching parameters of eight Acacia species were used to calculate three indices (stripping, biting and branching) describing different components of Acacia structural defences. These were combined to form an overall defence index that was tested against the results of three feeding simulation tests as well as actual animal feeding rates obtained from trials using nyala held in bomas. The stripping, biting and branching indices were shown to provide a good measure of the different components of a structural defence, although the scaling of their contribution to an overall defence index is complicated by variation in the suite of browsers and the resources available at a locality. The indices developed in this study provide a useful tool for assessing the role of large mammal herbivory in different environments when attempting to understand variation in the life history strategies of Acacias.
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Richards, Joseph L. "Systematics of Rhodolith-Forming Taxa of Corallinophycidae (Rhodophyta) from the Northwestern Gulf of Mexico and Panama." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163302.
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Comparative DNA sequence analyses of newly collected specimens of rhodolith-forming members of the Corallinophycidae (Rhodophyta), known as crustose coralline algae, from deepwater rhodolith beds offshore Louisiana in the Northwestern Gulf of Mexico and throughout the Gulf of Mexico revealed a wealth of previously undocumented diversity and many species new to science. Rhodlith-forming corallines span multiple lineages, including members of the Corallinales, Hapalidiales, and Sporolithales. Observations performed with scanning electron microscopy revealed the presence of characters congruent with those reported for each respective taxonomic group. Within the Corallinales, members of the Lithophyloideae and the genus Porolithon are represented offshore Louisana. The genus Lithothamnion (Hapalidiales) is polyphyletic and comprises at least 6 species. The order Sporolithales, represented by a species new to science, is reported for the first time offshore Louisiana and offshore Florida. Comparisons to specimens from Panama and Brazil revealed taxa that are closely related to specimens from the Gulf of Mexico. The DNA sequence data and SEM micrographs serve as a foundation that will facilitate continued research on members of the Corallinophycidae.
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Hastings, Jennifer Lynn. "Systematic and Ecological Studies of the Viola subsinuata Species Complex." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou153185551690636.
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Gibbons, Kerry Lynne. "Systematics of Loganieae (Loganiaceae), with an emphasis on the Mitrasacme alliance." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14131.
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Molecular phylogenetics has clarified the limits of the angiosperm family Loganiaceae, and of the Australasian-Pacific tribe Loganieae. However, generic circumscriptions within Loganieae require clarification. A molecular phylogeny confirmed the monophyly of Mitrasacme, with Phyllangium and Schizacme placed sister to each other and to Mitrasacme. The monophyly of Schizacme, including New Zealand taxa, was confirmed, and a review of Schizacme is presented. Mitreola minima was placed sister to Mitrasacme and its segregates, rather than with other members of Mitreola. A new monotypic genus, Adelphacme, is erected, and the morphological characters distinguishing it from Mitreola, Mitrasacme, Phyllangium and Schizacme are presented. Labordia was nested within Geniostoma. New combinations within Geniostoma are provided for sampled taxa. Logania sect. Logania and L. sect. Stomandra (syn. of Orianthera) were each monophyletic but Logania was non-monophyletic. Mitrasacme is the largest genus in Loganieae (c. 54 spp.). Its geographic range extends from Asia, Malesia and New Caledonia to southeastern Australia, but is centred in the Australian Monsoon Tropics. Species limits and the subgeneric classification of Mitrasacme were tested in a species-level molecular phylogeny. The monophyly of Mitrasacme, and relationships between Adelphacme, Mitrasacme, Phyllangium and Schizacme were confirmed. It is proposed that these four closely related genera be referred to as the Mitrasacme alliance. The current subgeneric classification in Mitrasacme is not supported, but a new subgeneric classification is hindered by morphological homoplasy and nested evolution. Three independent lineages in Mitrasacme extend into temperate eastern Australia, and multiple recent dispersals into Malesia and Asia are postulated. Morphological evolution in Mitrasacme might reflect adaptation to stochastic rainfall, oligotrophic soils and diverse insect pollinators in the Australian Monsoon Tropics.
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Wenzel, Aaron. "Systematics of Penstemon section Ericopsis, a group of plant species native to the Intermountain West." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1471533204.
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Sinn, Brandon Tyler. "Phylogenetic relationships, systematics, character-associateddiversification, and chloroplast genome evolution in Asarum(Aristolochiaceae)." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448379569.
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Memory, Andrew Edmund. "What Factors Influence the Success of Senecio (Asteraceae) in Canterbury, New Zealand? A Phylogenetic and Ecological Study." Thesis, University of Canterbury. School of Biological Sciences, 2012. http://hdl.handle.net/10092/7468.
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Abstract
Senecio is one of the largest genera in the Asteraceae family with 28 Senecio species in New Zealand and over 1200 species worldwide. Native Senecio in the Canterbury region are typically naturally uncommon and exhibit extreme fluctuations in population size. Contrary to native Senecio, exotic Senecio in the Canterbury region are thriving. Why some exotic species thrive in a novel environment while native species decline has been an area of intense study since the era of Darwin. However, despite extensive study, we are still unsure about the underlying mechanisms of this phenomenon. This thesis looks at several hypotheses that have been proposed to explain differences in success between native and exotic species including four that have been frequently mentioned in the literature: phylogenetics, natural enemy release and biotic resistance, allopolyploidy and habitat modification.
In order to determine if phylogenetic relatedness influences the abundance and distribution of Senecio species in Canterbury, DNA phylogenies of New Zealand’s Senecio were constructed using nuclear (ITS, ETS) and plastid (trnL, trnL-F and psbA-trnH) DNA sequences. The resulting cladograms were used to determine the areas of origin of New Zealand’s Senecio lineages, the identity of their closest relatives and lineages and species that are of allopolyploid origin. The data provided by the phylogenetic analyses was to provide context for analyses of ecological data of 86 native and exotic Senecio populations from the Canterbury region. My results indicate that phylogenetic relatedness is a poor predictor of the amount of folivory experienced by Senecio, although some natural enemies of native and exotic Senecio displayed a positive preference for Senecio depending on their clade. The strongest effects on Senecio and the occurrences of their natural enemies came from the surrounding land use which influenced the amount of folivory and the abundances of natural enemies on Senecio. Enemy release and biotic resistance were land use specific within Canterbury and by themselves cannot explain the variance in folivory when applied to a landscape scale. According to my results, the biggest factor influencing Senecio folivory, abundance and distribution in the Canterbury region is change in the surrounding land use.
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Silveira, Daniela Sampaio. "Revisão taxonomica das especies neotropicais extra-amazonicas de Sloanea L. (Elaeocarpaceae) na America do Sul." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315603.
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Orientador: Vinicius Castro SouzaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-14T10:53:10Z (GMT). No. of bitstreams: 1 Silveira_DanielaSampaio.pdf: 13077358 bytes, checksum: 444d6c94d072cef289968c110c821bf3 (MD5) Previous issue date: 2009
Resumo: Elaeocarpaceae inclui 15 gêneros, com aproximadamente 500 espécies distribuídas em regiões tropicais e subtropicais do globo, em com exceção dos continentes africano e europeu. O gênero Sloanea reúne 120 táxons, dos quais cerca de 40 ocorrem no Brasil em diversos tipos de vegetação, principalmente na Floresta Amazônica e na Floresta Atlântica. O presente trabalho refere-se à revisão taxonômica das espécies neotropicais extra-amazônicas de Sloanea. A realização deste estudo constou de levantamento bibliográfico, consulta aos acervos dos principais herbários nacionais e estrangeiros, e expedições de coleta em áreas de ocorrência natural dos táxons do gênero. De um modo geral, com base na morfologia externa, a caracterização de Sloanea compreende árvores de grande porte dotadas de sapopemas, folhas simples, flores com sépalas que podem ou não cobrir órgãos reprodutivos na fase pré-antese, estames com prolongamento do conectivo conspícuo, que pode ser agudo, acuminado ou filiforme, frutos cobertos por cerdas rígidas ou flexíveis, algumas vezes inermes. Na revisão foram definidas 19 lectotipificações aqui desginadas, quatro novas sinonimizações, um nome duvidoso e a constatação de cinco nomes ilegítimos e seis nomes nus. Foram identificadas 17 espécies na área de estudo, sendo seis desconhecidas para a ciência: S. fasciculate, S. filiforms, S. hatschbachii, S. petala, S. subssesilis, S. uniflora.
Abstract: Elaeocarpaceae includes 15 genera, witch approximately 500 species distributed in tropical and subtropical regions of the globe, except for African and European continents. Sloanea comprises 120 taxa, of witch about 40 occur in Brazil in several vegetation types, but mainly in the Amazon Forest and in the Atlantic Forest. This thesis revises the taxonomy of the neotropical species of extra-amazon Sloanea genus. This study consisted of literature review, consultation with the collections of major Brazilian and foreign herbaria, and collection expeditions in areas of natural occurrence of taxa of the genus. In general, based on external morphology, the characterization of Sloanea comprises large trees endowed with buttressed roots, simple leaves, flowers witch sepals that may cover or not the reproductive organs in pre-anthesis phasis, stamens with the connective continued into a small knob, acuminate, acute or filiform awn, fruit covered with rigid or flexible bristles, sometimes unarmed. In this thesis 19 lectotypes her designated were defined, and four new synonyms, one doubtful name, five illegitimate names and six nude names were found. From the 17 species that were identified in the studied area, six of them were unknown to science: S. fasciculate, S. filiforms, S. hatschbachii, S. petala, S. subssesilis, S. uniflora.
Universidade Estadual de Campi
Biologia Vegetal
Doutor em Biologia Vegetal
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Lee, Chung-Kun. "Phylogeny and Taxonomy of Commelinaceae (Commelinales)." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263508.
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Simon, Marcelo F. "Systematics and evolution of Mimosa L. (Leguminosae) and the assembly of a neotropical plant diversity hotspot." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497097.
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Roets, Francois. "Ecology and systematics of South African Protea-associated Ophiostoma species." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019.1/1469.
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Bucheli, Sibyl Rae. "Systematics of the megadiverse superfamily gelechioidea (Insecta: Lepidoptera)." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124119415.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xx, 389 p.; also includes graphics (some col.). Includes bibliographical references (p. 332-345). Available online via OhioLINK's ETD Center
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Cox, Antony V. "The utility of 5S rDNA in phylogenetic reconstructions : development of the polymerase chain reaction in plant systematics." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260639.
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Forster, Paul I. "The pursuit of plants : studies on the systematics, ecology and chemistry of the vascular flora of Australia and related regions /." [St. Lucia, Qld], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18317.pdf.
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Bergh, Nicola Georgina. "Systematics of the Relhaniinae (Asteraceae-Gnaphalieae) in southern Africa : geography and evolution in an endemic Cape plant lineage." Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/8933.
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Includes bibliographical references (p. 161-194).The Greater Cape Floristic Region (GCFR) houses a flora unique for its diversity and high endemicity. A large amount of the diversity is housed in just a few lineages, presumed to have radiated in the region. For many of these lineages there is no robust phylogenetic hypothesis of relationships, and few Cape plants have been examined for the spatial distribution of their population genetic variation. Such studies are especially relevant for the Cape where high rates of species diversification and the ongoing maintenance of species proliferation is hypothesised. Subtribe Relhaniinae of the daisy tribe Gnaphalieae is one such little-studied lineage. The taxonomic circumscription of this subtribe, the biogeography of its early diversification and its relationships to other members of the Gnaphalieae are elucidated by means of a dated phylogenetic hypothesis. Molecular DNA sequence data from both chloroplast and nuclear genomes are used to reconstruct evolutionary history using parsimony and Bayesian tools for phylogeny estimation. The subtribe is found to be nonmonophyletic, and three independent Cape-centred clades are identified. These constitute the earliest-diverging lineages in the Gnaphalieae. Ancestral areas are reconstructed onto the tree using maximum likelihood and indicate a Cape origin and diversification for the Gnaphalieae, with subsequent, multiple dispersals out of southern Africa. A relaxed Bayesian clock is used to estimate dates for important events, calibrated using a combination of secondary age estimates, fossil pollen and geological events. The single inferred dispersal to Australasia, which may be responsible for the large diversity of the tribe there, is compared with other dated trans-Indian Ocean disjunctions, and results in a hypothesis of direct Miocene longdistance trans-oceanic dispersal facilitated by the West Wind Drift. Important directions for future biogeographic and systematic studies on the Gnaphalieae are identified. One of the Cape clades identified in the above study, the Stoebe clade, is investigated using the same molecular markers and an additional chloroplast DNA region, in order to reconstruct relationships amongst the species and test generic circumscription. One genus, Amphiglossa, is found to be non-monophyletic and a recommendation is made to resurrect the genus Pterothrix in order to maintain monophyly. Relationships amongst subclades in the Stoebe clade can not be resolved, possibly due to a paucity of chloroplast DNA polymorphisms. Ancestral-state reconstruction using maximum likelihood indicates a high degree of homoplasy in all the macro-morphological characters used by previous workers to delimit the genera that fall within this polytomy (Disparago, Elytropappus and Stoebe). The evolution of these leaf, synflorescence and floral morphological characters is examined in order to shed light on the degree of homoplasy exhibited by each, and the patterns of character-state change across the tree. The analysis provides insight into patterns of morphological evolution, laying the groundwork for re-evaluation of characters previously thought to be homologous. The need for a rigorous, systematic anatomical study including all members of the clade is highlighted and some previously little-explored characters are identified that might provide greater future taxonomic insight. Due to a poor palaeoclimatic record, the impact of Pleistocene climatic fluctuations on the palaeodistributions of plant species in the Greater Cape Floristic Region is largely unknown. One of the members of the Stoebe clade, the common and widespread shrub Elytropappus rhinocerotis, is examined using population genetic tools in order to explore the spatial distribution of genetic variation and to infer the degree and pattern of responses (range shifts, population extinction) to recent (Quaternary) climatic changes. A molecular fingerprinting tool, inter-simple sequence repeat (ISSR) PCR is used to examine populations from across the range of E. rhinocerotis in order to compare patterns of population genetic diversity with the long-noted and strong spatial patterns of plant species diversity in the CFR. A large amount of genetic variation is detected, which is apportioned largely amongst individuals within populations rather than amongst populations or regions. This is to be expected for an outcrossing and well-dispersed plant species. However, there is significant spatial structure and a very uneven distribution of diversity across the geographic range of E. rhinocerotis. Although areas that have high species-diversity also generally exhibited high genetic diversity, the eastern margin of the range and the Kamiesberg highlands both have a far higher relative genetic diversity in E. rhinocerotis than would be predicted by their relative species diversity. This indicates that the processes producing greater leves of species diversity in some parts of the CFR are different than the processes responsible for high genetic variation within E. rhinocerotis populations. Geographic distance is a poor predictor of genetic distance between localities, especially towards the east of the range. This may be due to range alteration over the time-scale reflected by ISSR polymorphism. Inter-SSR variation declined from south to north in the western arm of the range, consistent with the prediction of Holocene aridification starting first and being most extreme in the north. Areas shown by the marker to harbour populations with high levels of variability include most parts of the eastern arm of the range, and the Kamiesberg highlands. The present study constitutes a demonstration of the range of evolutionary questions that can be addressed using a range of molecular phylogenetic and population genetic techniques, and the elucidation of both deep and shallow evolutionary history of a single Cape floral lineage.
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Salomaki, Eric D. "A Systematic Investigation of Batrachospermum section Helminthoidea (Batrachospermales, Rhodophyta) Using Molecular and Morphological Analyses." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1343077226.
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Duncan, John A. "Aloe Pillansii on Cornell's Kop : are population changes a result of intrinsic life history patterns or climate change?" Bachelor's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/25928.
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Aloe pillansii populations in the biodiversity hotspot of the Succulent Karoo in Southern Africa are thought to be under threat of extinction. This study investigated the population at the type locality; Cornell's Kop in the Richtersveld, South Africa. It has been suggested that theft, animal damage and more recently climate change have caused a decline in the population by over 50% in the last decade, however very little is known about this rare species. Repeat photography and surveys were used to analyse life history patterns and dynamics of the population and thus establish what the potential threats to this keystone species actually are. Repeat photography indicates that there have been high rates of adult mortality over the last fifty years (1.8% of the population dies annually), which results in an average predicted lifespan of 39 years for the remaining adult population on Cornell's Kop. However, a recent survey reported that over 40% of the population recorded were seedlings, which weren't found in a 1995 survey, which is indicative of a recent recruitment pulse on Cornell's Kop and that conditions on the hill are still habitable for A. pillansii. Growth analyses suggest that A. pillansii has an average annual growth rate of 20 mm.yr⁻¹, which in tum means that 8 m individuals may be up to 453 years old. This long-lived strategy would require A. pillansii to only recruit infrequently, during periods of high rainfall, in order to sustain a viable population, which is consistent with findings on other large desert succulents. Seedling ages were estimated from their heights and it was found that 50% of the seedlings appear to have germinated five to ten years ago; this is consistent with rainfall records from the area which indicate that rainfall was consistently above the annual average for this same period. The findings indicate that although the adult A. pillansii population is declining, the presence of 30 seedlings suggest that the population is entering a recruitment phase after just coming out of a lengthy senescent phase. Although A. pillansii 's extensive lifespan makes it a potentially useful indicator species of climate change, the evidence presented in this study does not suggest that climate change has affected the dynamics of this population.
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Lawrence, Daniel. "Systematic Revision within the Pleosporaceae and Identification of Processes that Occlude Phylogenetic Reconstruction." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/223349.
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The hypothesis of horizontal gene transfer of a hybrid gene from bacteria to the filamentous Ascomycota was tested using constrained phylogenetic analyses and tests of topological congruence. Results suggest that the hybrid gene was acquired from bacteria by a single transfer before the radiation of the Leotiomyceta. The phylogenetic relationship among Nimbya and Embellisia was investigated using both morphological and molecular data. Examination of conidia morphology revealed that Nimbya and Embellisia comprise two and four distinct morphological groups, respectively. Molecular analyses support all morphological groups of Nimbya and Embellisia and reveal that both genera are polyphyletic. Results suggest the circumscription of these genera is based upon convergent morphological characters. To further understand the evolutionary relationship among Alternaria and closely related genera, ten protein-coding genes were sequenced across 176 species. Three genes possessed significant substitution saturation and two other genes did not possess sufficient phylogenetic signal to assess relationships among the asexual Alternaria. The remaining five loci revealed strong support for asexual Alternaria and the order of divergence among eight asexual Alternaria species-groups. The current polyphyly of Alternaria was resolved using morphological and molecular data. Morphological examination revealed that most members of the infectoria clade (sexual Alternaria) produce diagnostic colony characters on dichloran rose bengal yeast extract sucrose agar (DRYES) and weak potato dextrose agar (WPDA) that are fundamentally different as compared to other small-spored Alternaria species. These data also revealed that all members of the infectoria clade produce arachnoid vegetative hyphae with multiple primary conidiophores, whereas other small-spored Alternaria species do not. Phylogenetic analyses revealed that the sexual infectoria clade clusters with other sexual genera phylogenetically distant to the asexual Alternaria. Lastly, the validity of taxonomy and the phylogenetic relationship among three small-spored Alternaria species was examined. Total ortholog comparisons and whole-genome comparisons revealed that the DNA sequence of A. alternata ATCC 11680 has a higher percent similarity to A. tenuissima EGS 34-015 than to A. alternata EGS 34-016. This suggests that these two isolates share a more recent common ancestor and A. alternata EGS 34-016 is more distantly related.
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Kahraman, Ahmet. "Morphology, Anatomy And Systematics Of The Genus Salvia L. (lamiaceae) In East And Southeast Anatolia, Turkey." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613416/index.pdf.
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This study aims to revise the genus Salvia L. in East and Southeast Anatolia in Turkey on the basis of macromorphological, anatomical, palynological, mericarp micro-morphological, ecological and numerical analysis. Towards achieving this goal, about 2500 specimens of Salvia were collected and examined during extensive field studies between July 2005 and June 2009. The materials collected by other researchers either from Turkey or abroad were also investigated.
The results of the taxonomic revision show that the study area includes 59 taxa, 24 (40.7%) of which are endemic and the remaining 35 (59.3%) are non-endemic. Salvia siiirtica is described as new to science. S. macrosiphon is described as a new record for Turkey and S. cerino-pruinosa and S. pseudeuphratica are re-evaluated as valid species as well as S. ballsiana is rediscovered.
Macromorphological characters that were considered to have taxonomically diagnostic value are investigated and their possible variations are discussed. Habit, stem, leaf, inflorescence, bract, calyx, corolla and stamen properties are compared at infrageneric and species level.
The first comprehensive evaluation of the systematic value of anatomy, palynology and mericarp micromorphology of Salvia are presented. Some characters, such as row numbers of ray cells in the root, type of the leaf blade structure, shape of cross section of the petiole, shape and number of median vascular bundles, pollen size, size of mericarps and diameter of abscission scars, are useful for infrageneric delimitation. Variation in some anatomical characters, such as number of cell layers of collenchyma and cortex, number of cell layers of palisade parenchyma, size of petiole, number of lateral vascular bundles, exine ornamentation type of pollen, presence of large lumina in the middle of the primary lumen, the muri thickness, mericarp shape, mericarp length/width ratio and surface ornamentation type, can be used for separating species within the sections.
Based on the updated geographical and ecological distribution, conservation status of the taxa is reassessed at regional, national and global levels. At the regional scale, the distribution is CR for 6 taxa EN for 9 taxa, VU for 5 taxa, NT for 10 taxa and LC for 29 taxa. At the national scale, the distribution is CR for 5 taxa, EN for 5 taxa, VU for 7 taxa, NT for 10 taxa and LC for 32 taxa. At the global scale, the distribution is CR for 5 taxa, EN for 3 taxa, VU for 6 taxa, NT for 10 taxa NT and LC for 35 taxa. The main threats in the study area are overgrazing, constructions, land clearing, fire, urbanization and tourism.
The infrageneric delimitation is performed using multivariate analysis. Identification keys to sections and species are given. Synonymy, updated descriptions, phenology, distribution and habitats in Turkey, general distribution outside Turkey, distribution maps, phytogeography, specimen citations, some notes on taxonomy and photographs showing general appearance of the taxa are also provided.
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Heathcote, Steven John. "The ecology of vascular epiphytes in the Peruvian Andes." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:d7bee986-6066-48a1-8849-4aed22a3d766.
Full textAbstract:
Little is known about the composition of tropical epiphytic communities and the influence of environmental variables on community composition. In this thesis I quantify the diversity and biomass of bromeliads, and other vascular epiphytes along an altitudinal transect on the eastern slope of the southeast Peruvian Andes and then look for species’ adaptations related to patterns of diversity and biomass. I compare patterns with those of woody species. Bromeliad species, like tree species, were found to form ecological zones related to climate. The lowest altitude ecological zone (below 1250 m) is the lowland rainforest (LRF), which has the warmest climate and highest evapotranspiration. In LRF vascular epiphytes are less prominent than other ecological zones, with the lowest bromeliad species richness and lowest vascular epiphyte biomass. However, low water-availability gives rise to most variable shoot morphology of bromeliads. The tropical montane forest (TMF), between 1250 m and 2250 m, is intermediate in climate between the LRF and the tropical montane cloud forest (TCF). The TMF has the highest α-diversity, but species richness is lower than the TCF. The shoot morphology of bromeliads is intermediate between TCF and LRF. The highest altitude ecological zone with forest is the TCF (above 2250 m). The TCF has the highest bromeliad species richness, and lowest diversity of shoot forms. The low diversity of shoot forms represents the need for a large phytotelm (water-impounding shoot) to intercept and store precipitation. The TCF has the highest vascular epiphyte biomass, although the biomass is variable as a consequence of the natural disturbance caused by landslides. Along the transect bromeliad species with CAM photosynthesis are only present in the LRF. Terrestrial bromeliad distribution records covering the Neotropics show CAM photosynthesis is more prevalent in drier environments showing that CAM photosynthesis is primarily an adaptation to drought. Epiphytic bromeliads, pre-adapted to a water-stressed environment show no differences in presence along rainfall gradients, but species with CAM photosynthesis occupy warmer environments.
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Martínez-Habibe, María Cristina. "Systematics, Biogeography and Leaf Anatomy and Architecture of Bursera subgen. Bursera (Burseraceae) in the Greater Antilles and the Bahamas." Scholarship @ Claremont, 2012. http://scholarship.claremont.edu/cgu_etd/49.
Full textAbstract:
This dissertation presents a comprehensive study on the origin and evolutionary relationships of the species of Bursera in Cuba, Hispaniola, Jamaica and the Bahamas. The goals of the first chapter were to test monophyly of the group, revisit a recent transfer of two species of Bursera to Commiphora, and place recently discovered mainland species using the reconstructed phylogenies. Additionally, divergence estimations using fossils were used as independent tests of several hypotheses regarding the arrival of the modern biota to the Greater Antilles and Bahamas (GAB). I conclude that all endemic taxonomic entities of the genus in this region belong to Bursera subgen. Bursera but that two separate lineages colonized the GAB via dispersal. The genus diversified during the Middle Miocene to Pliocene, and the data corroborate several paleogeographic events during that interval. The second chapter presents informative characters from leaf anatomy and leaf architecture for the 14 endemic species of Bursera distributed in the GAB. There is evidence for some evolutionary tendencies in the group, among them a trend toward small, simple, amphistomatic and unifacial leaves, character states for which ecological correlates can now be studied. Morphological and anatomical evidence corroborates phylogenetic results in suggesting that a population of B. glauca in Cuba is a new species. Finally, the third chapter constitutes the first taxonomic account and description of all known endemic species of Bursera in the region and reflects the results of the previous chapters. The primary results are as follows: (1) a new species from eastern Cuba, B. yaterensis, is described; (2) five species of Commiphora are returned to Bursera; (3) B. nashii is treated as conspecific with B. glauca; and (4) B. ovata is treated as conspecific with B. trinitensis. A dichotomous key is provided using mostly vegetative characters due to the frequent lack of adequate reproductive material and the relative uniformity of most floral and fruit characters. Each species description includes leaf architecture (morphology and venation pattern) and anatomy, introducing characters that could and should be used for describing and distinguishing other Bursera in Meso- and South America as well as for African Commiphora.
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Lewin, Marcus. "Taxonomic revision of the genus Chamaecrista (Fabaceae) in Ecuador." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-242636.
Full textAbstract:
A revision of the genus Chamaecrista (Leguminosae) in Ecuador is presented. The work is based on morphometric studies of herbarium material and information from the literature and the Internet. The purpose of the study was to get a better knowledge of the distribution, taxonomic status and conservation of Chamaecrista in Ecuador. The study recognizes in all six species and several varieties, viz. Ch. nictitans with var. jaliscensis, var. disandea, var. pilosa, var. paraguariensis and var. glabrata, Ch. glandulosa with var. flavicoma and var. andicola, Ch. absus and Ch. rotundifolia. Keys, descriptions and illustrations are provided for all taxa.
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Hemery, Gabriel E. "Juglans regia L : genetic variation and provenance performance." Thesis, University of Oxford, 2000. http://ora.ox.ac.uk/objects/uuid:160d3486-f71c-4575-84e7-85dc64b3222f.
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A range-wide collection of Juglans regia seeds was undertaken in autumn 1997 from 12 countries, including 25 provenances and 375 half-sib progenies. 2200 seedlings were produced using innovative nursery techniques. The seedlings were planted in three provenance trials in southern England in 1999, the largest of which acted as a combined provenance/progeny trial. After one growing season, survival was 98.9 %, mean height growth 35 cm, and mean stem diameter increment 5 mm. Provenance differences for both height and stem diameter increment were highly significant (p<0.001). There were no significant genotype × environment interactions. Flushing assessments revealed few significant differences between provenances and flushing was complete by early April. Family heritability for tree height was 0.19 at one site and, with combined selection, genetic gain was estimated at 8 %. The effects of three types of treeshelter and a stumping treatment on walnut establishment were tested over three growing seasons. Treeshelters were found beneficial to height increment. However, 120 cm tall shelters promoted early flushing, and consequent risk of increased frost damage, and caused more stem die-back than 75 cm shelters. Stumping promoted rapid early height increment but gave no longer-term benefit. The crown (cd) and stem (dbh) diameter at breast height relationship of open growing trees in Britain was assessed and was highly significant (r2 = 0.96, p<0.001). The regression equation (cd = 2.71 + 17.6dbh) permitted the estimation of suitable planting densities for the provenance trials and the calculation of a thinning regime. Isozyme analysis of the 375 genotypes identified 20 loci in 15 enzyme systems with seed embryo extracts. Using young leaf extracts, the polymorphic locus Pgm-1 indicated low expected heterozygosity of 0.06 both within populations and at the species level. FST and GST estimates, both 0.05, indicated high uniformity among populations. Genetic distance estimates did not identify significant clustering consistent with geographic origin.
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Nakamura, Nodoka. "Dissecting the Japanese hotspot : refining evaluation of biodiversity in forests at different scales in the Japanese landscape." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c625c75e-b983-48ab-b8c8-fbe0cea0d53e.
Full textAbstract:
Japan is one of the world’s 34 biodiversity hotspots, according to Conservation International (CI). The methods used by various organisations to define priorities differ, however, and all have weaknesses when trying to identify hotspots at finer resolutions. The goal of this thesis is to investigate how biodiversity hotspots in Japan could be revealed and mapped in order to encapsulate conservation elements of biodiversity in practical ways and at various scales. Bioquality is a term that emphasises the concentration within a community of elements of biodiversity with high conservation value. It evaluates the global rarity and taxonomic distinctiveness of plant species or infra-specific taxa using four Star categories. At a plant community level, the Genetic Heat Index (GHI), which is a standardised global range size rarity score, is calculated using weighted Star statuses of species in the community. Bioquality hotspots are assessed here for the first time for the flora and vegetation in Japan – and for temperate Asia – by categorising the Japanese flora into Stars and by applying GHI to survey data and literature-based sources. Keys to Stars are developed for the Japanese flora, with adjustments for variability in species geographic range size information and for taxonomic relatedness. A Flora of Japan (FOJ) database was compiled as a BRAHMS database, containing 8,262 accepted names (30,656 taxon names in total, including synonyms) in 258 families – the first full database of Japanese vascular plants. A total of 7,145 taxa are assigned Stars; from the rarest to the widespread class, there are 884 Black, 756 Gold, 833 Blue, and 4,672 Green Star taxa, confirming that Japan as a whole contains a high proportion of globally rare taxa (23% taxa in Black or Gold). A protocol for calibrating the weight of Stars based on species geographic range is developed based on fine-resolution distribution maps within Japan and coarse–resolution Taxonomic Database Working Group (TDWG) code information. The protocol optimises calculation for temperate regions. The first ever bioquality hotspot maps of Japan are produced using two independent data sources on species distribution at national level: 1) 50 botanical prefectures using 4,830 species from the FOJ database; 2) 1,418 Horikawa ‘geoquadrats’ (0.1° latitude by 0.15° longitude grid) maps covering 829 species. The Ryukyu Islands and Ogasawara Islands are identified as bioquality hotspots, and high mountain ranges in mainland Japan are predicted to contain areas potentially high in GHI; the spatial patterns of GHI are generally concordant between maps of different resolutions. These findings highlight that bioquality assessment can be applied meaningfully at various spatial resolutions. Using field sampling data and existing literature, three study sites are further investigated on a local level: 1) the satochi-satoyama landscape, the current national priority area for biodiversity conservation; 2) various vegetation types of Okinawa-jima Island, the Ryukyu Islands; and 3) the Utaki sacred groves within the predicted hotspot of the Ryukyu Islands. The Ryukyu Islands are confirmed to contain bioquality hotspots within many individual sites, while there was generally low GHI across the satochi-satoyama landscape. The field study outcomes, together with a gap analysis of the existing coverage of protected areas, highlight three important points that are directly relevant to national biodiversity conservation planning: 1) the Ryukyu Islands urgently need newly designated protected areas; 2) the satochi-satoyama landscape conservation should redirect its focus on cultural benefits to the public; 3) the existing protected areas, particularly on mountain areas, need re-evaluation in terms of upgrading their status in light of the bioquality assessment.