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Molecular sequence data from two noncoding regions of DNA (ITS AND TRNL-F) were used to produce a phylogeny for the genus Tribolium and its African and Australasian allies. Topological comparisons of the combined molecular data with the appended existing morphological tree were made. A significant incongruence was revealed. Molecular data indicate that Tribolium is paraphyletic. The formally defined sections: Uniolae, Acutiflorae and Tribolium have been retrieved by the molecular data. The analysis retrieved Karroochloa as polyphyletic. Monophyly of Schismus is strongly supported. The Australasian species form a monophyletic clade. Data support early divergence of the Merxmuellera species and Pseudopentameris macrantha.

Two Trichilogaster sp. (gall-forming wasps) have been introduced against Acacia longifolia and Acacia pycnantha in the Cape. Trichilogaster acaciaelongifoliae has reduced both seed production (by between 85 and 100% in the Cape) and vegetative growth in Acacia longifolia. The aim of this project was to determine whether the galls and buds of Acacia pycnantha have significantly different energy values, and to determine what affect this has on the plant. There was no significant difference between gall and bud energy values (p=0.029, df-=7, alpha=0.05) but gall energy values were, on average, 9.35% lower than those of bud material. The mass of galls increased steadily throughout the year while bud material remains at the same weight. The resource loss to the plant caused by the galls is dependent on the size and number of galls present on the tree. Even with similar energy values per unit dry mass there were many more grams of gall material on a tree than bud material and thus they would demand more resources to be invested in the gall material. An important factor concerning the effect galling has on A. pycnantha is the time during the trees reproductive cycle that galling occurs. It has been shown that when galling coincides with the season when the most energy is channelled into reproduction that the damage to the tree is heaviest.

Bibliography: leaves 106-120. / The genus Euphorbia is morphologically diverse and nearly cosmopolitan. Both succulent and non-succulent species are found within the genus. Succulent species are found in most arid and semi-arid areas of the world, but show their greatest concentration and diversity of form in Southern Africa especially the Cape Floristic Region. The monophyly and phylogenetic relationships of the genus Euphorbia were investigated based on morphology and on sequences of the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast psbA-trnH intergenic spacer. Fifty-one species of Euphorbia and four outgroups from Monadenium and Ciutia were sampled. Matrices were analysed using parsimony and maximum likelihood methods. Separate analyses of data partitions resulted in largely non-conflicting topologies; therefore the data sets were combined. The results showed that the genus Euphorbia is paraphyletic and four monophyletic groups with a number of putative synapomorphies defining each clade were strongly supported in most analyses. The Cape succulents fall into two well-supported clades. The results thus provided evidence for Cape radiations. Most analyses indicated that one of the Cape groups is sister to a group consisting of species mostly from Southern Africa (excludingthe Cape Region). Increased taxon sampling is however needed to clarify relationships within the monophyletic groups. Morphological characters recovered broad groups within Euphorbia. Due to inadequate sampling in some sections, modifications in the present classification of Euphorbia are not suggested. The total evidence tree was used to explore morphological character evolution through character state optimisations. The presence of root tubers was homoplasious and this character state is hypothesized to have arisen at least five times under current sampling. Cylindrical stems, conspicuous leaves and absence of leaf spines were some of the pleisiomorphic states observed in some sampled members of the genus Euphorbia. Although the results obtained in the CUlTent study are preliminary, they have created further challenges for future studies of phylogenetic relationships and morphological character evolution in the genus Euphorbia.

Includes bibliographical references. / This study examines the effects of fragmentation on bryophyte diversity in renosterveld vegetation of South Africa's west coast. The main objectives of this study are to; Document bryophyte species assemblages in remnant fragments of renosterveld vegetation, investigate the effect of fragment size, isolation and heterogeneity on bryophyte diversity patterns in renosterveld, determine the extent to which fragments are nested and evaluate the extent to which existing conservation measures are appropriate for the long-term survival of the bryophyte flora in this vegetation type. Seventy-two bryophyte species were recorded from 23 fragments ranging from 0.1 to 102 hectares.

Hoodia Sweet ex Decne is revised to contain 13 species which are divided into 2 sections. Sect. Hoodia contains H.currorii, H.dregei, H.gordonii, H.juttae and H.parviflora. Sect. Trichocaulon contains H.alstonii, H.flava, H.mossamedensis, H.officinalis, H.pedicellata, H.pilifera, H.ruschii and H.triebneri, all except H.ruschii formerly constituting the section "Eutrichocaulon", the so-called "spiny" species of Trichocaulon. The remainder of Trichocaulon, the section Cactoidea, is transferred to Lavrania Plowes. This genus then consists of the monotypic section Lavrania (L.haagnerae) and Sect. Cactoidea containing L.cactiformis, L.marlothii, L.perlata and L.picta.

Bibliography: leaves 86-97. / Lepfodon smithii (Leptodontaceae) and Pterogonium gracile (Leucodontaceae) are widespread and disjunctly distributed moss species, that in South Africa are confined to forest patches believed to be relics of vast forests that existed before the Pleistocene glaciation period. These two species exhibit similar distribution and ecologies and frequently co-occur. Wardia hygrometrica is a southwestern Cape endemic that is restricted to streams within the kloofs that the forests generally occupy. In an attempt to trace the species histories and their subsequent colonization of forest patches, two molecular markers, internal transcribed spacer (ITS) nuclear rDNA and trnL-F cpDNA were employed.

Bibliography : leaves 64-79. / Both Ulva and Enteromorpha are very common, ubiquitous, and environmentally important genera of green seaweeds. The evolutionary history of Ulva species is poorly understood, stemming from a lack of diagnostic, non-molecular systematic characters. This study addresses the following questions: i) Do the two genera represent distinct entitiesj ii) What are the relationships among local putative species; iii) Do the recognized species represent monophyletic lineages; iv) How closely are local species related to those from elsewhere? These questions are addressed using nuclear ribosomal DNA ITS sequences from 48 local samples plus data on 16 samples from GenBank.

Bibliography: leaves 58-64. / The taxonomy of Dryopteris inaequalis complex is reviewed. The use of a large sample size permitted quantification of variation within and among groups. Phenetic methods in this study revealed the existence of six groups, five formerly described taxa and one new taxon, D. pseudopentheri sp. ined. The new species is defined on both macromorphological grounds. Dryopteris lewelleana Pic.Serm. and d. inaequalis (Schltdl.) Kuntze var. atropaleacae Schelpe are placed in synonymy under D.fadenii Pic.Serm. and D.inaequalis respectively. The phylogeny of the complex is reconstructed using cladistic analysis of morphological characters. Dryopteris manniana (Hook.) C.Chr., the probabl sister species is used as an outgroup for the analysis. Phylogenetic analysis revealed that there are four monphyletic species and two metataxa in the complex. Evidence from Scanning Electron Microscopy, micromorphology, macromorphology and cytology is used as a basis for classification. Trichome characters, indusium, spore and guard-cell sizes proved to be of great taxonomic utility in defining species and cytotypes in the complex. Guard-cell and spore sizes in the different taxa are positively correlated to ploidal level. Illustrations of some microcharacters are provided. The taxonomic treatment includes a key, descriptions of the species based on the characters studied and a distribution map.

Bibliography: leaves 89-101. / This study expands on existing molecular (rpoC2 and ITS) and morphological data sets to further test the hypothesis of non-monophyly of Merxmuellera sensu lato. The results reveal that despite high levels of resolution, the morphological data yield poorly supported phylogenies due to high levels of homoplasy in the dataset.