Thesis (Ph. D.)--Uppsala University, 1998. / Includes bibliographical references (p. 188-199).

Thesis (Ph. D.)--Uppsala University, 1998. / Includes bibliographical references (p. 188-199).

Thesis (Ph. D.)--State University of New York at Binghamton, Sociology Department, 2005. / Includes bibliographical references.

M.Sc. / A biosystematic study of the genus Sutherlandia (L.) R. Br., a poorly studied genus with confusing geographical variants, is presented. The species of Sutherlandia are all endemic to southern Africa. The species are very closely related and problems regarding their taxonomy are discussed. A few morphological characters that are useful in distinguishing amongst species are illustrated and discussed in detail. Morphological data are used to investigate infrageneric relationships in a phenetic analysis of 51 geographically separated populations. Sutherlandia has traditional medicinal uses, mainly as an anti-cancer treatment for internal cancers and as a general tonic. A survey of chemical compounds was done and the results are illustrated and presented in tables. The nature of this study did not allow detailed medical investigations, but the medicinal value of Sutherlandia and the compounds detected are highlighted. It is suggested that the anti-cancer activity can mainly be ascribed to the high levels of canavanine, a non-protein amino acid, in the leaves of the plant. Canavanine, an arginine analogue, is known for its antitumourigenic properties. The value of the plant as a bitter tonic is probably related to the presence of several triterpenoids, some of which may well also have other beneficial effects. Enzyme electrophoresis was done to explore genetic relationships amongst the numerous regional forms of Sutherlandia. A study of 19 populations showed that they are all closely related and that a more conservative treatment of the taxa is called for. As a result the number of taxa is reduced. A complete taxonomic revision of the genus is presented. The number of species is reduced from six to two, namely S. frutescens and S. tomentosa. The former is divided into three subspecies, namely subsp. frutescens, subsp. microphylla and subsp. speciosa. Some regional forms are described and illustrated, but these are not formally recognised as taxa. A key to the species, subspecies and regional forms is provided, and the. nomenclature, typification, description and geographical distribution for each of the taxa are given. The multidisciplinary approach of this study provided a better understanding of the morphological, chemical and genetic variation in this relatively poorly known but potentially valuable ornamental and medicinal plant.

Dissertation (PhD)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The previous revision of Zygophyllum L. by Van Huyssteen (1937) included all known species of the cosmopolitan genus Zygophyllum. The present study deals with the species of Zygophyllum occurring in the southern African region which includes Angola, Namibia, Botswana and South Africa. The majority of Zygophyllum species occur in the arid and semi-arid, western parts as well as in the interior parts but some species do occur to the south of the area where milder climatic conditions are experienced. Zygophyllum species are typically described as shrubs or shrublets, rarely herbaceous annuals or biennials, with simple, sessile leaves or sessile, bifoliolate or petiolate, bifoliolate leaves of a succulent texture. Macromorphological as well as phytogeographical data were studied in order to delimit the taxa and to determine their relationships as well as their distributions. Various tables summarizing diagnostic characters of taxonomic importance as well as line drawings depicting the salient features of the species are given. The division of the genus Zygophyllum into two subgenera was investigated and this division is corroborated with additional evidence concerning floral, fruit and seed morphology. The absence or presence of an elaiosome on the seeds found in the two subgenera reflects on their different dispersal strategies. The structure of the morphologically different mucilage produced by the seeds of the two subgenera is touched on. The division of the subgenera Agrophyllum (Neck.) End!. and Zygophyllum, each into several sections, was investigated. Two sections, one from each subgenus, were transferred: the monotypic § Morgsana (Huysst.) Van Zyl to subgenus Zygophyllum; and the monotypic § Grandifolia Eng!. to subgenus Agrophyllum. The § Prismatica Van Zyl is newly described and the §Annua Eng!. is reinstated. seventeen new species are described, a few names sunk into synonymy and several name changes made. / AFRIKAANSE OPSOMMING: Die vorige hersiening van Zygophyllum L., deur Van Huyssteen (1937), het alle bekende spesies van die kosmopolitaanse genus Zygophyllum ingesluit. Die huidige studie handel slegs oor die Suider afrikaanse Zygophyllum-spesies wat in Angola, Namibië, Botswana en Suid-Afrika voorkom. Die meerderheid Zygophyllum spesies groei in ariede en semi-ariede dele aan die weskus asook in die binneland van die area maar sommige spesies groei ook in die suide van die gebied met 'n meer gematigde klimaat. Zygophyllum-spesies word beskryf as struike of halfstuike, is selde kruidagtige, een- of tweejariges en het gewoonlik eenvoudige, sittende blare of sittende verdeelde of gesteelde verdeelde, sukkulente blare. Makromorfologiese en geografiese data is bestudeer om die verskillende taxa af te baken, om verwantskappe tussen die onderskeie spesies vas te stel sowel as om die verspreiding vir elke takson aan te gee. Tabelle met die vernaamste taksonomies kenmerke asook lynsketse van die mees belangrike kenmerke van die verskillende species word verskaf. Die verdeling van Zygophyllum in twee subgenera is ondersoek en is, met behulp van bykomende blom-, vrug- en saadmorfologiese inligting, volkome regverdig bevind. Die aan- of afwesigheid van elaiosome op sade dui op verskillende saadverspreidings metodes. Die morfologies-verskillende slymlaag wat deur die saad van die twee subgenera produseer word, is kortliks beskryf. Die verdeling van die subgenera Agrophyllum en Zygophyllum in verskeie seksies is ondersoek. Die monotipiese subseksie Morgsana word na subgenus Zygophyllum en die monotipiese § Grandifolia na subgenus Agrophyllum verskuif. Die § Prismafica word as nuut beskryf en die § Annua word in hergebruik geneem. Sestien nuwe spesies word beskryf, enkele name word in sinonimie geplaas.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, for the degree of Master of Science. Johannesburg 1993. / The prediction that savanna communities with similar conditions of plant available moisture (PAM) and available nutrients (AN) have similar structural and functional features was tested for a range of southern African savanna types. This prediction forms the basis of an hypothesis that savannas can be classified functionally on the basis of PAM and AN. Nineteen South African savanna types were sampled over a rainfall gradient of 369 to 690 rnm pa and on different geological parent materials. Ecologically meaningful indices of PAM and AN were derived using climate and soil physical and chemical data. The floristic structural and functional characteristics of the woody plant and herbaceous components of the savanna communities were ordinated and classified in relation to the PAM and AN gradients. The functional classifications were assessed in the plane of PAM and AN. Plant available moisture was indexed as the mean number of growth days per annum derived form a water balance modelling approach. This index reflected the duration of the growing season in days and was suitably detailed for use at the community level. The AN indices ranged in complexity from a measure of the availability of individual nutrients in the soil to an index based on the results of a bioassay experiment. The usefulness of the AN indices was assessed on a number of criteria and the soil A horizon total nitrogen content in mg/kg was chosen as a suitable AN index. The species composition of the woody plant and graminoid communities was primarily related to the PAM gradient with AN having a significant but secondary effect. There was overall a high degree of similarity between woody plant and graminoid floristic types. The distribution of members of the woody plant families, Mimosoideae, Caesalpinoideae and Combretaceae were primarily related to the AN gradient. The higher taxonomic classifications of the graminoid communities, based on subfamilies and tribes, were primarily related to PAM. Structural trends of the woody plant and herbaceous communities were related to the PAM gradient but not to soil fertility. There were a range of structural types for similar conditions of PAM and AN. The functional trends of the woody plants were primarily related to the AN gradient with PAM having a secondary but significant effect while the graminoid community functional trends were primarily related to PAM with AN having a secondary but significant effect. The woody plant and graminoid communities were notgrouped into functional types in the same way. It was evident from this study that these South African savanna types were related floristically, structurally and functionally to either or both of PAM and AN, which are hypothesised to be the primary determinants of savanna structure and function. Although communities with similar conditions of PAM and AN were not consistently functionally similar, the functional classifications of both the woody plant ami graminoid communities mapped well onto the PAM-AN plane. This indicated that the PAM-AN plane does have potential foruse as an overall framework for the classification of savannas on a functional. basis. / AC2017

MSc., Faculty of Science, University of the Witwatersrand, 2011 / A selection of southern African bird species were modelled in terms of the probability of these species colliding with or being electrocuted on overhead power lines in South Africa, based on morphological and behavioral factors. Species were included in the model on the basis of internationally recognized vulnerability to these interactions at the family level. The collision model performed poorly when tested against the actual reported mortalities for species contained in the Eskom-EWT Strategic Partnership Central Incident Register CIR)(chi-square of goodness of fit) at the individual species, family and within family levels. The electrocution model performed slightly better at the family, and within family level. Both collision and electrocution models performed better for the physically larger species (and families) and for those species with higher modelled probability of collision or electrocution. As the product of random carcass detection and reporting, the CIR data are biased in various ways. Testing the models against the CIR is therefore equally important for highlighting inadequacies in the CIR, as in the model. A number of new species have emerged as being of high collision (including most importantly African Pygmy Goose, Southern Ground Hornbill, Black-bellied Bustard, Yellow-throated Sandgrouse, Caspian Tern, Hooded Vulture, Bateleur, African Marsh Harrier, Black Harrier, Pink-backed Pelican and Yellow-billed Stork) or electrocution (Southern Bald Ibis) probability in theoretical terms, and will require further investigation to determine their actual probability of interaction. By mapping the combined distributions of those species with high probabilities of collision and/or electrocution mortality, a number of priority high risk geographic areas emerge around the country.

M.Sc. / A taxonomic revision of the genus Rafnia Thunb. (= Oedmannia Thunb., Vascoa DC., Pelecynthis E. Mey), a relatively poorly known papilionoid legume genus, is presented. Rafnia (family Fabaceae, tribe Crotalarieae) is subendemic to the fynbos region of the Western and Eastern Cape Provinces of South Africa, with one species having a distribution area reaching into KwaZulu-Natal. The species delimitation has been unsatisfactory, and the relationships among the taxa uncertain. Rafnia is divided into two sections and 19 species are recognized, compared with the 22 species previously distinguished by Harvey (1862). There are five new species and four species are subdivided into subspecies, eight of which are described for the first time. There are eight changes of status and one new combination is made. Rafnia constitutes a total of 31 taxa. Morphological data used to investigate relationships among the species of Rafnia are analyzed phenetically and cladistically and keys to the sections, species and subspecies, complete nomenclature, typification, descriptions as well as the geographical distribution for each of the taxa are presented. Proposals are made to resolve troublesome uncertainties regarding the nomenclature and typification of some species. The scope of this study did not permit detailed investigation into chemical or molecular evidence, although preliminary studies showed that such data would improve the understanding of the infrageneric relationships within the genus. Characters and character states show much variation, but an hypothesis of the phylogenetic relationships amongst the taxa is nevertheless presented. An in-depth study of morphological characters in particular has resulted in a better understanding of taxonomic relationships at the generic and infrageneric levels in Rafnia.

Please read the abstract in the 07summary part of this document / Thesis (PhD (Botany))--University of Pretoria, 2007. / Plant Science / unrestricted

The study of landforms has, to a large extent been neglected by exploration geologists. This is surprising because field geology is intimately related with landforms of one type or another. An understanding of the geomorphological history of a particular area will assist in the appreciation of the surficial environment, the processes of weathering, soil formation and duricrust (calcrete , ferricrete silcrete) formation. This has direct application in planning and interpreting geochemical sampling programmes. In order to understand the evolution of landforms it is necessary to study slope development in some detail. Agents of erosion and denudation constantly at work, remove detritus from hillcrests down to the drainage lines which form the local base level from whence material is transported down to the sea. The system is one of dynamic equilibrium, and the concept of grade is important in understanding hillslope evolution. Thus Section (1) of this discussion deals with past and present theories of hillslope evolution. Very little work has been done recently on the geomorphology of Southern Africa and the presently accepted classification of land surfaces is based on the work of Prof. L.C. King (numerous publications). However, through the more recent work of De Swardt and Bennet (1974) on the geomorphology of Natal, it is apparent that the present system of landform classification in Southern Africa requires widespread revision. The relationship of erosion cycles in Southern Africa to the late Jurassic-early Cretaceous break-up of Gondwanaland has received insufficient attention in the past. Erosion cycles bear an intimate relationship to offshore Cretaceous and Tertiary-Recent sedimentation. Valuable information on these sediments has only recently become available as a result of offshore exploration for oil. The findings of De Swardt and Bennet (1974) are summarized in Section (2) and the present land surface classification of Southern Africa is reviewed. Finally, some suggestions on a new interpretation of land surfaces in Southern Africa are given.