M.Sc. / Please refer to full text for abstract

The revision of Metalasia by Karis (1989) made it clear that the rest of the Metalasia group, as defined by Anderberg (1991a), also needed to be investigated. Anderberg (1991a) identified the Relhania and Metalasia groups in the subtribe Relhaniinae of the tribe Gnaphalieae. The Metalasia group consists of 14 genera, of which seven are monotypic and four have recently been described. The monotypic genera Bryomorphe, Dolicothrix and Phaenocoma are well known, whereas the more recently described Atrichantha, Calotesta, Hydroidea and Planea (Hilliard & Burtt, 1981; Karis, 1990) are known from limited collections. In the broader context of the tribe it also became evident that Disparago (Koekemoer, 1993), Stoebe and Elytropappus (Levyns, 1937, 1935b) needed to be re-assessed to establish the rank of their formal and informal groupings. A number of genera in the group: Amphiglossa, Bryomorphe, Lachnospermum, Phaenocoma and Pterothrix, had not been studied since Flora Capensis (Harvey, 1865) and needed attention. The aims of this study were therefore, to clarify the taxonomy and nomenclature, to provide full taxonomic treatments for all the species in the Metalasia group, and to discuss their phylogenetic relationships. The fact that almost all taxa are endemic to southern Africa provided additional motivation to investigate the group. Furthermore the newly described genera and species have not been studied in the context of the whole group and the large number of specimens that are available today add a wealth of new information to the available knowledge. The need for further investigation was also emphasized by comments by Anderberg (1991a) that Elytropappus and Stoebe are probably paraphyletic or polyphyletic and that Amphiglossa is probably paraphyletic if Pterothrix is kept separate. Extensive fieldwork was undertaken to investigate species in their natural habitat. Spirit-preserved and dried specimens were collected and studied in the herbarium. Thorough morphological studies were undertaken, with extensive use of the SEM and light microscopes; photographs were produced to document the characters. Accurate records were kept of all specimens to assist in determining distribution ranges for each taxon as well as species densities for every genus. Anatomy of selected species was investigated. The results revealed that the leaves of Dolicothrix and Dicerothamnus were indeed glandular, that there are two small resin cavities in the leaf bases of some Seriphium species, and for the first time, provided information on leaf and cypsela anatomy for the group. During the course of this study several nomenclatural problems were solved: the correct name for Bryomorphe aretioides; Klenzea lycopodioides is a synonym of Dolicothrix ericoides, rather than of Bryomorphe; and the confusion around the names Elytropappus gnaphaloides and E. glandulosus was cleared. It was also found that Elytropappus hispidus and E. cyathiformis, and Stoebe cyathuloides and S. sphaerocephala are conspecific. On generic level it was found that Amphiglossa and Pterothrix are congeneric; and that Disparago, Elytropappus and Stoebe are paraphyletic. This resulted in Seriphium being re-surrected for a group of Stoebe species, and Disparago being divided into four genera and Elytropappus into three. Taxonomic treatments for 64 species, including nomenclature, synonymy, typification, full descriptions, geographical distribution, and keys to genera and species, are given. Fieldwork resulted in a large number of new distribution records, the discovery of six new species and also the re-collection of two species (Amphiglossa callunoides and A. corrudifolia) that were only known from type specimens and were thought to be extinct. Although attempts were made to investigate the group, both chemically and cytologically, I was not able to do this successfully. Chemical results indicated that the volatile oils and flavonoids are complex and would provide a wealth of information for future studies. Together with DNA investigations in the Gnaphalieae it could possibly assist to unravel existing uncertainties. A summary of the taxonomic implications of this study is given below: Genera New species No of species Taxonomic implications Amphiglossa A. celans, A. grisea A. rudolphii, A. susannae 11 • Pterothrix as synonym with several new combinations • Four new species • P. flaccida and P. spinescens as synonyms Atrichantha 1 Bryomorphe 1 • Nomenclature clarified Calotesta 1 Dicerothamnus 2 • New genus • New combinations Disparago 4 • Reverting to original concept of Gaertner for the genus • Three new genera created Dolicothrix 1 • Klenzea lycopodioides as new synonym Elytropappus E. aridus E. monticola 3 • E. cyathiformis as synonym • Genus split into three Gongyloglossa 1 • New genus • New combination Hydroidea 1 Lachnospermum 3 • Nomenclature clarified Laevicarpa 1 • New genus • New combination Metalasia 52 Monticapra 3 • New genus • New combinations Myrovernix 5 • New genus • New combinations • M. intricata transferred from Stoebe Phaenocoma 1 Planea 1 Seriphium 9 • Resurrect the genus • New combinations • Elytropappus ruscianus, Stoebe burchellii and S. vulgaris as synonyms Stoebe 16 • S. copholepis, S. ensori, S. sphaerocephala, S. humilis, S. salteri and S bruniades as synonyms. Total 117 Characters and character states were evaluated in terms of their taxonomic value and their contributions towards an improved understanding of phylogenetic relationships amongst the genera and species of the Metalasia group. The patterns of character state distributions were explored, using cladistic methods. This resulted in the discovery of several ‘new’ characters, as well as new ways of interpreting some of the ‘old’ characters. Examples include several very interesting observations made by means of SEM studies; e.g. the true identity of Elytropappus cyathuloides, the glands on the leaf surfaces of Dicerothamnus rhinocerotis, D. adpressus and Dolicothrix ericoides as well as resin cavities at the bases of leaves of some Seriphium species. All data gathered from the study were evaluated and analyzed cladistically to determine inter- and infraspecific relationships. New hypotheses regarding the relationships amongst the genera and species of the Metalasia group are presented. / Van Wyk, B.E., Prof.

M.A. (African Languages) / Africa encompasses such a variety of languages and language types that even today linguistic science is somewhat at a loss to describe the mutual relationships between all these languages. This study is concerned with the Sotho group of Bantu languages. The existing classifications of the Sotho group are examined with regard to the classification criteria employed and how consistently and correctly these have been applied. A critical consideration of these classifications brings to light a considerable number of problems which show the classifications to be inadequate. The conclusion is drawn that the various criteria need to be reconsidered and that the requirements for a well-founded, ideal classification of Sotho should be clearly spelled out. Three basic approaches to the problem are dealt with, namely: a purely synchronic linguistic. classification, a genealogical classification based on diachronic principles, and a sociolinguistic classification. In each case the applicability to Sotho of the method concerned, given the present state of knowledge, is evaluated. As regards a synchronic linguistic classification, it is shown that clarity is needed. concerning crucial terms such as "language" and "dialect"; that a hierarchy of criteria has to be determined; that mutual influences and the influences of non-related languages should be allowed for; and that different degrees of relatedness should be accounted for. Given that these problems are addressed satisfactorily and given that sufficient data is available, a wellfounded synchronic classification would be possible. In the case of a genealogical classification, the use of reconstructions of proto forms of the Bantu languages, such as those of Meinhof and Guthrie, and of reconstructions of Proto-Sotho, such as that of Dickens, is considered...

Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2006. / Microbiology and Plant Pathology / Unrestricted

This work provides a phylogenetic classification of the insect order PSOCOPTERA. Some of the problems involved, mainly arising from lack of adequate published data, are pointed out and work carried out to overcome them is indicated in a short introductory chapter (Chapter I). This consisted of accummulating data on the genera from published texts and illustrations, adding data from the study of fresh material or material held in collections and compiling generic definitions in adequate detail where possible. Chapter II gives a general description of the Psocoptera together with brief background information on their biology. As considerable changes are proposed in the classification of the order (in Chapter VII) the classification in use at present is set out for comparison to generic level and a brief history of systematic work on the order is given {Chapter III). The data necessary for a discussion of the phylogeny is presented in the series of definitions of genera and suprageneric groups in Chapter IV. Data on fossil forms is given in Chapter V. The principles of phylogenetic study are briefly discussed in Chapter VI and the important question of the relatively primitive or advanced condition of characters in the order is discussed. The monophyly of the order and the relationships between genera are established using Hennig's system and the results are set out in discussion and dendrogram. On the basis of the relationships so established a classification of the order is proposed which is considered to be practical and to reflect evolutionary history of the group. (Chapter. VII.) Comments on the distribution of the Psocoptera are made in Chapter VIII and it is suggested that, despite inadequacy of data, a consideration of the distributions supports the proposed classification in general terms. A general discussion follows and references and figures are included. An appendix provides a practical up-to-date key to the genera of the order.

No abstract available. / Dissertation (MSc (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

Previous taxonomic studies culminated in the current differentiation of the mitosporic fungal genera Drechslera, Curvularia, Bipolaris and Exserohilum. The circumscription of Drechslera and Exserohilum are generally accepted and supported by the association with the teleomorphic ascomycetous genera Pyrenophora and Setosphaeria respectively. The separation of Curvularia and Bipolaris, both anamorphs of Cochliobolus, has been disputed. Many highly similar species have been described that share features of more than one genus. In this study 45 strains representing 14 species of Bipolaris, Curvularia and Exserohilum were characterised with regard to spore morphology, growth characteristics in culture and host preferences. Nucleic acid-based methods were used to evaluate the status of current morphological species. Integration of all this information represents a new approach to the taxonomy of this group. A list of Bipolaris, Curvularia and Exserohilum species known to occur in South Africa is provided and confrrmed their host relations presently known from the literature and includes eight new records. The stability of various spore dimensions and physiological reactions of cultures was analysed by using First Order Inductive Logic (FOIL) and a Decision Tree (DT) algorithms. Both tools proved spore shape to be more consistent than dimensions, and that colony diameter on days three to five, provided measurements with the best diagnostic value. Colony growth rates can be diagnostic within the long-spored species (fusoid to cylindrical spores) but not between the short-spored (clavate to navicular spores) species of the Bipolaris-complex. Differences in colony diameters from five of 25 culture-based tests enabled FOIL to differentiate between species with 79% certainty. Partial sequencing of the 28S rRNA encoding gene differentiated between Exserohilum species and a second group including Bipolaris and Curvularia species. The molecular marker type, Inter-simple sequence repeats (ISSR) using four anchored primers DBD-(AC)7, BDB-(CAC) 5, DHB-(CGA) 5 and VHV -(GT) 7G, were used with the similarity coefficients of Dice and Pearson and the clustering method of Ward to reveal various levels of intra-specific variability. ISSR data indicated greater similarity between Cochliobolus anamorph species with three to four septate conidia than the species with multiseptated conidia. All short-spored species investigated are plurivorous while the long-spored species seem to have a definite graminicolous host preference. Based on these observations it is proposed that the genera Curvularia and Bipolaris be retained as distinct taxa but amended: plurivorous mitosporic Cochliobolus species with short, clavate or navicular spores should be assigned to Curvularia and mitosporic Cochliobolus species with fusoid to cylindrical spores with gramicolous host preferences should be assigned to Bipolaris. The study confrrmed Exserohilum to be a well-defmed genus. Exserohilum inaequale was found to be synonymous with C. cymbopogonis. Two species, separated only on spore length, E. longirostratum and E. rostratum should be retained since they are also distinct in physiology and ISSR patterns. Integration of physiological traits, spore dimensions, host relationships and ISSR fingerprint patterns can therefore enhance the taxonomy of the Bipolaris complex. / Thesis (PhD (Botany))--University of Pretoria, 2005. / Plant Science / unrestricted

No description available.

The circumboreal Polypodium vulgare complex consists of a series of closely related ferns of different ploidy levels. Two northwestern North American members of the complex, P. glycyrrhiza D. C. Eaton, and P. hesperium Maxon, have long been a source of taxonomic confusion since little has been known of their relationships within the complex in the Northern Hemisphere. The present cytotaxonomic investigation of these taxa has shown that they are composed of three cytotypes, two diploid and one tetraploid. P. glycyrrhiza has proved to be uniformly diploid (n = 37) and morphologically, ecologically and geographically distinct from P. hesperium. Investigation of P. hesperium has shown that this taxon, as usually treated by North American taxonomists, is composed of at least two distinct entities, one tetraploid (n = 74), the other diploid (n = 37). These two cytotypes are morphologically and ecologically as well as cytologically separable, and have independent geographical distributions. The type specimen of P. hesperium is morphologically comparable to tetraploid populations from the interior of British Columbia, and specimens from the type locality have proved to be tetraploid. It is recommended that P. hesperium be reserved for the tetraploid cytotype. The epithet montense is tentatively proposed for the diploid cytotype. Two morphologically distinct triploid hybrids were found in areas of sympatric occurrence of the three cytotypes. Morphologically these hybrids appear to be P. hesperium x P. glycyrrhiza and P. hes-perium x P. montense. At meiosis both hybrids showed n II • n I, which is interpreted to mean that the montense genome and the glycyrrhiza genome are both present in P. hesperium. P. hesperium sensu stricto appears to be of alloploid rather than autoploid origin since it forms only bivalents at meiosis. P. hesperium is also intermediate in morphology and ecology between P. glycyrrhiza and P. montense. It is postulated that P. hesperium is an allotetraploid derived from a pre-Pleistocene hybridization between r. glycyrrhiza and P. montense or their immediate progenitors. The hypotnesis is also made that P. hesperium originated largely because of climatic changes in the interior of the continent imposed by pre-Pleistocene orogenic activity. Morphology, ecology and geographical distribution indicate three main lines of differentiation among the diploid cytotypes. These diploids eventually gave rise to polyploid derivatives, probably in the late Tertiary before the advent of Pleistocene glaciation. The intergradation and morphological variability of these taxa are attributed to alloploidy, hybridization and phenotypic plasticity. The morphology, biochemistry, ecology and geographical distribution of the three species is circumscribed and discussed and a pragmatic key provided. / Science, Faculty of / Botany, Department of / Graduate

As people across the globe are becoming more interested in watching their weight, eating more healthily, and avoiding obesity, a system that can measure calories and nutrition in everyday meals can be very useful. Recently, there has been an increase in the usage of personal mobile technology such as smartphones or tablets, which users carry with them practically all the time. In this paper, we proposed a food calorie and nutrition measurement system that can help patients and dieticians to measure and manage daily food intake. Our system is built on food image processing and uses nutritional fact tables. Via a special calibration technique, our system uses the built-in camera of such mobile devices and records a photo of the food before and after eating it in order to measure the consumption of calorie and nutrient components. The proposed algorithm used color, texture and contour segmentation and extracted important features such as shape, color, size and texture. Using various combinations of these features and applying a support vector machine as a classifier, a good classification was achieved and simulation results show that the algorithm recognizes food categories with an accuracy rate of 92.2%, on average.