The moss genus Andreaea possesses some sporophyte features that resemble liverworts or mosses and some gametophyte features resembling only the mosses, whereas other features are unique. This thesis presents the first phylogenetic study of the genus, based on both morphological and molecular evidence. Gametophyte and sporophyte characters were utilised for cladistic analysis. Sequence data was also generated from two chloroplast gene loci, the trnL-F intergenic spacer and the coding region of the ribosomal protein S4 (rps4). Separate morphological and molecular analyses produced topologies incongruent in certain parts and congruent in others. However, their combined analysis was better supported and therefore offered a more reliable hypothesis. The inferred phylogeny supported the monophyly of the genus. However, the monophyly of most infra-generic groups was largely contradicted. The putative subgenus Chasmocalyx is monotypic with A. nivalis as the sole species, whereas A. australis and A. nitida were resolved within the more broadly circumscribed section Andreaea of subgenus Andreaea. The section Nerviae of subgenus Andreaea is more narrowly circumscribed. A. blyttii (presumed member of section Nerviae) forms a basal lineage separate from all other species and apparently should constitute another monotypic subgenus. A. wilsonii (traditional Subgenus Acroschisma) is embedded within section Andreaea of Subgenus Andreaea. A. subulata, a presumed member of the section Nerviae (Subgenus Andreaea) is included in the section Andreaea. Character state optimisation has shown that falcate leaves, possession of a leaf costae and medium sized spores are some of the pleisiotypic features within Andreaea. However, a number of phylogenetic questions, regarding infra-generic relationships of the genus still remain unanswered. Directions for further future work have been suggested.

The Cape (CFR) is an exceptional centre plant This diversity is concentrated in a profusion geographically restricted endemic species within a The CFR is a rich and dynamic for the molecular study of speciation, but until recently studies have focused on factors influencing diversification of whole lineages, than on details the speciation process within and between species pairs.

The Cape (CFR) is an exceptional centre plant This diversity is concentrated in a profusion geographically restricted endemic species within a The CFR is a rich and dynamic for the molecular study of speciation, but until recently studies have focused on factors influencing diversification of whole lineages, than on details the speciation process within and between species pairs.

Hypodontium is a moss genus currently comprising two species, H. dregei and H. pomiforme, endemic to Southern Africa, occurring in Zimbabwe and the eastern and southern parts of the Flora of Southern Africa areas. lt was originally assigned to the family Calymperaceae but was recently moved to Pottiaceae. The two families do not differ absolutely and Hypodontium possesses combinations of characters that could place it in either. This study used molecular DNA sequence data from two chloroplast gene regions, tmLtmF and rps4, to investigate the family status of the genus. The results obtained showed that it is not a member of either Calymperaceae or Pottiaceae, and supports the erection of a new family to accommodate Hypodontium. Hypodontium pomiforme occurs as two distinct morphological forms, and it has been suggested that these two forms might constitute two separate species. This study used both morphological (cluster analysis and Canonical Discriminant Functions Analysis) and molecular (nuclear ITS sequences) data to test this hypothesis. Results of both methods support the idea of significant difference between the two forms. Three species are therefore proposed for the genus Hypodontium, with H. humilopapillosum Manyanga & Hedderson described as new. A key is provided for the three species along with brief descriptions and a distribution map for each.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2005. / The family Oxalidaceae has a worldwide distribution, but is most common in tropical and subtropical regions. Oxalis L. is the largest genus of the family comprising ca. 800 of the 900 species. Oxalis species are annual or perennial herbs or rarely subshrubs or trees. The current study assesses on the taxonomic placement of O. furcillata Salter. Currently this species, comprising two varieties, O. furcillata var. furcillata and O. furcillata var. caulescens Salter, is placed in section Foveolatae. Members of this section have endospermous seeds and fleshy leaflets. However, both in terms of leaf morphological and seed characters the two varieties of this species appear to be misplaced within this section. In addition O. furcillata var. caulescens has a unique pollen type, different from both the typical variety and the rest of the section. Both lines of evidence thus suggest that O. furcillata var. caulescens may be misplaced within this section. The present study thus sets out to assess the placement of O. furcillata in general, and the placement of O. furcillata var. caulescens in particular. A multi-disciplinary approach was followed, which included analyses of macro-morphological (including LM and SEM analyses), biogeographical and palynological characters. The variability of quantitative characters was assessed using the STATISTICA 6.0 software package. Leaf dimensions, plant height, bulb length, petiole length and palynology showed sufficient differences between the two taxa to confirm the separate identity of these two varieties as separate species. O. furcillata var. caulescens was thus raised to specific status as O. caulescens (Salter) Bissiengou. The results suggest two different options in terms of the taxonomic placement of the species O. furcillata and O. caulescens. They can either remain in section Foveolatae, best placed near O. senecta and O. densa or may moved to the highly variable section Latifoliolatae. But retaining them within the section Foveolatae appeared to be the better alternative. The correct position will be established both through further morphological analyses and correlation to the trnL-F and ITS sequence-based phylogeny of the southern African members of Oxalis.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2005. / At present a proper systematic classification of the southern African members of Oxalis L. (Oxalidaceae) does not exist. The most recent and comprehensive revision of the genus based on macro-morphological characters is out-dated (published 60 years ago (Salter, 1944)). The external morphology of the flowers of the southern African Oxalis species is reasonably wellstudied, but little is known about the anatomy thereof. A pilot study of fruit and seed morphology and anatomy of nine selected southern African Oxalis species (Obone, 2003) already revealed some trends to demarcate two main groups. This confirmed the systematic value of some of the characters already proposed by Salter (1944). The aim of the present study was to assess the potential systematic value of fruit and seed morphology and anatomy of 32 Oxalis species. The selection was done such that the included species would represent the main sections proposed by Salter (1944), the pollen types proposed by Dreyer (1996) and the different clades revealed by the phylogenetic tree compiled by Oberlander et al. (2004). Although the species sampling was very low (20% of the southern African taxa), 35 potentially informative characters were identified in fruit and seed morphology and anatomy. These characters may be grouped into three character types, namely autapomorphic characters, randomly distributed characters and systematically informative characters. The first two character types were particularly useful in species-specific characterization. The third group of linked characters could be used to demarcate two major groups of species, those producing endospermous seeds and those producing exendospermous seeds. The three types of characters may prove to be taxonomically informative if more species-inclusive studies are performed. The cluster analysis strongly supported the demarcation of endospermous and exendospermous groups with 100% bootstrap support. Low bootstrap values were observed for subgroups within each of the major groups. This is probably due to low taxon sampling. Therefore clustering based on fruit and seed morphology should be considered with extreme caution within the two groups. Despite these limitations of sample size, fruit and seed morphological and anatomical characters have proven to be systematically informative at the infra-generic level.

Thesis (MSc)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: Erica is a genus of about 860 species world wide, with 700 of these found in South Africa’s southwestern and southern Cape, making it by far the most speciose genus in the Cape Floristic Region. This poses a particular challenge in the construction of a molecular phylogeny of the genus. The choice of suitably variable gene regions is a crucial decision on which the successful phylogenetic reconstruction of this important genus is critically dependent. The aim of this project was therefore to determine which DNA regions, both chloroplast and nuclear, would be sufficiently variable to give adequate informative characters that may be useful at the species level phylogenetic reconstruction. A subset of 30 species, representing the range of morphological diversity and pollinator preference within Erica, was selected for study. For each of these species the variability in eight chloroplast regions (trnL-F, matK, trnS-G, rps12- rpl20, psbAtrnH, trnC-D, rps4-trnT and trnT-L) and the nuclear ITS region was investigated. The psbA-trnH, trnC-D, rps4-trnT and trnT-L chloroplast regions were found to be problematic to amplify and to possess too few Parsimony Informative Characters to be of use in phylogenetic reconstruction. Four of the chloroplast regions, trnS-G, trnL-F, matK and rpS12-rpL20 and the nuclear ITS region could be amplified and sequenced with success. The ITS region was found to be reasonably variable, with the chloroplast genes showing less variability. The DNA extraction method employed showed itself to be of critical importance in the success of the study. Two DNA extraction protocols, both modified from the original Doyle and Doyle (1987) method, were tested. The one included double the amount of β-mercaptoethanol and Polyvinylpyrrolidone (PVP) and the other included an extended phenol: chloroform: isoamylalcohol step. These variables, together with the effectiveness of these methods on fresh vs. silica dried plant samples, were investigated to determine which of the two would yield high quantities and qualities of DNA and result in the best method for the extraction of DNA from Erica species. / AFRIKAANSE OPSOMMING: Erica is ‘n genus van omtrent 860 spesies wêreldwyd, met 700 van hierdie spesies aanwesig in die suidwes en suid Kaap van Suid Afrika, wat dit by verre die mees spesieryke genus in die Kaapse Floristiese Streek maak. Dit stel ’n besondere uitdaging in die konstruksie van ’n molekulêre filogenie van die genus. Die keuse van geskikte variërende geen-areas is ‘n belangrike besluit waarvan die suksesvolle filogenetiese rekonstruksie van hierdie belangrike genus krities afhanklik sal wees. Die doel van hierdie projek was dus om te bepaal watter DNS areas, buide chloroplas en kern, genoegsaam varieer om voldoende informatiewe kenmerke te lewer om bruikbaar te wees in ’n spesie-vlak molekulêre rekonstruksie. ’n Subgroep van 30 spesies, wat die reeks van morfologiese diversiteit en bestuiwer voorkeure in Erica verteenwoordig, is dus vir die studie geselekteer. Vir elk van hierdie spesies is die variasie in agt chloroplast areas (trnL-F, matK, trnS-G, rps12- rpl20, psbA-trnH, trnC-D, rps4-trnT en trnT-L) en die kern ITS area ondersoek. Dit was problematies om die psbA-trnH, trnC-D, rps4-trnT en trnT-L chloroplast areas te amplifiseer, en daar is gevind dat hulle te min Parsimonie Informatiewe Kenmerke besig om bruikbaar te wees in filogenetiese rekonstruksie. Vier van die chloroplas areas, trnS-G, trnL-F, matK en rpS12-rpL20 en die kern ITS kon suksesvol geamplifiseer word en die basisvolgordes kon suksesvol bepaal word. Daar is gevind dat die ITS area redelik variërend is, terwyl chloroplas areas minder variasie getoon het. Die DNS ekstraksie metode wat gebruik is het die kritiese belang van die ekstraksie metode in die sukses van die studie bewys. Twee DNS protokolle, beide gemodifiseer van die oorspronklike Doyle en Doyle (1987) metode, is getoets. Die een het dubbel die hoeveelheid β-mercaptoetanol en Polyvinylpyrrolidone (PVP) bevat, en die het ’n uitgebruide fenol: chloroform: isoamylalkohol stap ingesluit. Hierdie veranderlikes, saam met die effektiwiteit van hierdie metodes op vars teenoor silika-gedroogde plant monsters, is ondersoek om vas te stel watter een van die twee die hoogste kwaliteit en kwantiteit DNS sou lewer en dus sal lei tot die beste DNS ekstraksie metode vir Erica spesies.