Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: Oxalis L. has two centres of diversity, one in South-Central America and the other in southern Africa. Previous palynological studies of southern Africa Oxalis revealed four main pollen types, namely rugulate-reticulate, micro-rugulate-spinate, reticulate and supra-areolate (Dreyer 1996). The reticulate pollen type is further divided into 15 subtypes, out of which five have a monotypic status. The supra-areolate pollen type is divided into four subtypes based on exine structure. The reticulate pollen type is the most common pollen type within the South African members of Oxalis. The three remaining main pollen types display more complex exine structures and are therefore considered more derived than the reticulate pollen type. The present study assessed the pollen of 50 American Oxalis species with three main objectives: 1. To observe pollen type variations among American members of Oxalis, 2. To compare pollen types from the two centres of diversity, and 3. To assess which centre of diversity house the palynologically more advanced species of Oxalis. Two main pollen types are recorded from the present study, namely reticulate and verrucate pollen types. The reticulate pollen type could be further divided into 11 subtypes. Out of the 11 subtypes observed, nine also occur among South African members of Oxalis, while two types are only observed in the American members of Oxalis. The verrucate pollen type is found in a single American taxon and displays a more complex exine structure than the reticulate pollen type. In this study the reticulate pollen type proved to be the most common pollen type among the American members of Oxalis. The South African members of Oxalis display more complex pollen types than the American members of the genus. / AFRIKAANSE OPSOMMING: Oxalis L. het twee diversiteitsentrums, een in Suid-Sentraal Amerika en die ander in suidelike Afrika. Palinologiese studies van suidelike Afrika Oxalis-taksa toon vier hoofstuifmeeltipes, naamlik gerimpel-netvormig, fyn-gerimpel-stekelrig, netvormig en supra-areolêr (Dreyer 1996). Die netvormige stuifmeeltipe word verder verdeel in 15 subtipes. Vyfvan hierdie tipes het 'n monotipiese status. Die supra-areolêre stuifmeeltipe word verdeel in vier subtipes gebaseer op eksienstruktuur. Die netvormige stuifmeeltipe is die mees algemene stuifmeeltipe aanwesig in die Suid Afrikaanse Oxalis-taksa. Die drie oorblywende hoofstuifmeeltipes toon 'n meer komplekse eksienstruktuur en word as meer gevorderd as die netvormig stuilmeeltipe beskou. In die huidige studie is stuifmeelkorrels van 50 Amerikaanse Oxalis spesies bestudeer met drie doelstellings in gedagte: 1. Om die variasie in die stuifmeeltipes van die Amerikaanse spesies van Oxalis te bestudeer, 2. Om die stuifmeeltipes van die twee diversiteitsentrurns te vergelyk, en 3. Om vas te stel watter diversiteitsentrum het palinologies die meer gevorderde spesies van die genus Oxalis. In die huidige studie is twee hoofstuifmeeltipes onderskei, naamlik netvormige en verrukate stuifmeeltipes. Die netvormige stuifmeeltipe is verder verdeel in 11 subtipes. Van die 11 subtipes wat onderskei is, kom nege tipes ook in die Suid Afrikaanse taksa van Oxalis voor, terwyl twee stuifmeeltipes slegs by die Amerikaanse soorte van Oxalis voorkom. Die verrukate stuifmeeltipe is slegs in 'n enkele Amerikaanse spesie gevind. Hierdie tipe toon 'n meer komplekse eksienstruktuur as die netvormige stuifmeeltipe. In die huidige studie het die netvormige stuifmeeltipe gebleik die mees algemene stuifmeeltipe in die Amerikaanse Oxalis-spesies te wees. Die Suid Afrikaanse taksa van Oxalis toon meer komplekse stuifmeeltipes as die Amerikaanse taksa.

Submitted by (edna.saturno@ufrpe.br) on 2016-06-29T13:05:56Z No. of bitstreams: 1 Maria Carolina de Abreu.pdf: 3697875 bytes, checksum: c00a83bedf9547f9ef58a0a8830f4a93 (MD5) / Made available in DSpace on 2016-06-29T13:05:56Z (GMT). No. of bitstreams: 1 Maria Carolina de Abreu.pdf: 3697875 bytes, checksum: c00a83bedf9547f9ef58a0a8830f4a93 (MD5) Previous issue date: 2007-02-26 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Oxalis L. is outstanding as the major genera of the famiiy Oxalidaceae, detaining around 800 species, approximately, 136 are found in Brazil. This work aimed to study the diversity of OxaIis in Pernambuco through morphological data. These data were based on the analysis of approximately 500 exsicates from the major Brazilian herbariums, as well as matenals obtained in field that, after processing, were incorporated to the herbanum Professor Vasconcelos Sobrinho (PEUFR). Oxalis is represented in Pernambuco by nine differentiated species, mainly by the shoot system, phylotaxy, type of leaf, color of the flowers, inflorescences and capsules in two subtypes and six sections: Oxalis corniculata L, O. cratensis Oliver, O. debilis Humb. Bonpl. & Kunth, O. divaricata Mart. ex Zucc., O. frutescens L, O. glaucescens Nolind, O. hedysarifolia Raddi, O. psoraleoides Humb. Bonpl. & Kunth and O. triangularis A. St-Hil. The species more widely distributed in the State were O. psoraleoides, O. frutescens and O. triangularis that are distributed from zones of the Coast and Forest up to the subzone of the Backwoods, though the first one in surrounding many people. OxaIis corniculata and O. cratensis are mainly distributed in Littoral and Forest zones up to Sertão subzone; Oxalis divaricata is distributed in the Agreste and Sertão subzones occurrinng also in the Fernando de Noronha Archipelago. Oxalis hedysarifolia habits in the Forest zone and in the Agreste subzone only in the mountains regions. OxaIis debilis is restricted to Agreste subzone in the edges of tropical montane forests and Oxalis glaucescens is exclusive to Sertão subzone, in sedimentary areas. / OxaIis L. destaca-se como o maior gênero da família Oxalidaceae, detendo cerca de 800 espécies das quais, aproximadamente, 136 são encontradas no Brasil. Este trabalho objetivou estudar a diversidade de OxaIis em Pernambuco através de dados morfológicos. Estes dados foram baseados na análise de aproximadamente 500 exsicatas oriundas dos principais herbános brasileiros, bem como de materiais obtidos em campo que, após processamento, foram incorporados ao acervo do herbáno Professor Vasconcelos Sobrinho (PEUFR). Oxalis está representado em Pernambuco por nove espécies diferenciadas, principalmente, pelo sistema caulinar, fliotaxia, tipo de folha, cor das flores, inflorescências e cápsulas, posicionadas em dois subgêneros e seis seções: Oxalis corniculata L., O. cratensis Oliver, O. debilis Humb. Bonpl. & Kunth, O. divaricata Mart. ex Zucc., O. frutescens L., O. glaucescens Norlind, O. hedysarifolia Raddi, O. psoraleoides Humb. Bonpl. & Kunth e O. triangularis A. St.-Hil. As espécies mais amplamente distribuídas no Estado foram Oxalis psoraleoides, O. frutescens e O. triangularis encontradas desde as zonas do Litoral e Mata até a subzona do Sertão, embora a primeira em diversos ambientes. Oxalis corniculata e O. cratensis distribuem-se preferencialmente nas zonas do Litoral e Mata até o inicio da subzona do Sertão; Oxalis divaricata, nas subzonas do Agreste e Sertão e no Arquipélago de Fernando de Noronha; Oxalis hedysarifolia, na zona da Mata e na subzona do Agreste apenas sobre serras; OxaIis debilis é restrita a subzona do Agreste nas bordas das florestas montanas e Oxalis glaucescens é exclusiva na subzona do Sertão, em áreas sedimentares.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-07-08T12:51:41Z No. of bitstreams: 2 Maria Carolina de Abreu 1.pdf: 9972417 bytes, checksum: e9add48ae3b4be0128892bfa910252f6 (MD5) Maria Carolina de Abreu 2.pdf: 9673154 bytes, checksum: fa7a39f4887913c5bc4e45d459e547a4 (MD5) / Made available in DSpace on 2016-07-08T12:51:41Z (GMT). No. of bitstreams: 2 Maria Carolina de Abreu 1.pdf: 9972417 bytes, checksum: e9add48ae3b4be0128892bfa910252f6 (MD5) Maria Carolina de Abreu 2.pdf: 9673154 bytes, checksum: fa7a39f4887913c5bc4e45d459e547a4 (MD5) Previous issue date: 2011-02-14 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The family Oxalidaceae R. Br comprises about 600 species in five genera. Noteworthy is the genus Oxalis L. as the most representative family with 500 species of tropical and subtropical distribution. This genus includes the most recent classification with four subgenera and 29 sections. Among the sections stands O. sect. Thamnoxys with 27 species of which eight are endemic to Brazil. Our objectives are to point out the relationships among the species of O. sect. Thamnoxys through the study of morphological phylogenetics, answering questions about the differentiation of species of this section occurring in Brazil and assess the character of the seed coat ornamentation in the delimitation of infrageneric and specific taxa. The study of phylogenetic relationships were based on 72 morphological characters and conducted by PAUP version 4.0b10, using the method of maximum parsimony. The analysis founded 53 equally parsimonious trees with 250 steps. The consensus tree showed CI = 0.32, RI = 0.4637 and RC = 0.1484. Oxalis sect. Thamnoxys proved to be paraphyletic by the inclusion of O. densifolia (O. sect. Foliosae) and subclade formed by O. cordata and O. hirsutissima (O. sect. Robustão), O. rhombovata (sect. Polymorphae), O. mandioccana (O. sect. Holophyllum), O. psoraleoides (O. sect. Psoraleoideae) and O. fruticosa (O. sect. Phyllodoxys) in its constituency and the subgenus Thamnoxys presented monophyletic. The species of the section Thamnoxys formed some subclades Foliosae section and was more closely related to section Thamnoxys. The taxonomic studies were based on approximately 2000 derived from herbarium specimens and herbarium collections themselves. In Brazil there are 18 species of Oxalis sect. Thamnoxys, differentiated mainly by vegetative characters related to the presence of xylopodium, shape, number and distribution of leaflets and indumentum reproductive character and coloration of the corolla. It was proposed to sinonimization four varieties and one form. The study of the microstructure of the seed coat was performed by scanning electron microscopy (MEV). The seed coat sculpture presented in five different categories: foveolar, sidetransverse, longitudinal-side, split-back and split longitudinally, which in part reflect the infrageneric classification of Oxalis. / A família Oxalidaceae R. Br. compreende cerca de 600 espécies distribuídas em cinco gêneros. Destaca-se o gênero Oxalis L. como o mais representativo da família com 500 espécies de distribuição tropical e subtropical. Este gênero engloba na classificação mais recente quatro subgêneros e 29 seções. Entre as seções ressalta-se O. sect. Thamnoxys com 27 espécies das quais oito são endêmicas do Brasil. Os objetivos deste trabalho foram: apontar as relações existentes entre as espécies de O. sect Thamnoxys através do estudo de filogenia morfológica, promover uma melhor diferenciação das espécies desta seção ocorrentes no Brasil e ainda avaliar o caráter ornamentação da testa da semente na delimitação de táxons infragenéricos e específicos. O estudo das relações filogenéticas foi baseado em 72 caracteres morfológicos e conduzidas através do PAUP version 4.0b10, pelo método de máxima parcimônia. A análise resultou em 53 árvores igualmente parcimoniosas com 250 passos. A árvore de consenso apresentou IC= 0,32, IR= 0,4637 e RC = 0,1484. Oxalis sect. Thamnoxys mostrou-se parafilética pela inclusão de O. densifolia (O. sect. Foliosae) e do subclado formado por O. cordata e O. hirsutissima (O. sect. Robustae), O. rhombeo-ovata (O. sect. Polymorphae), O. mandioccana (O. sect. Holophyllum), O. psoraleoides (O. sect. Psoraleoideae) e de O. fruticosa (O. sect. Phyllodoxys) em sua circunscrição e o subgênero Thamnoxys apresentou-se monofilético. As espécies da seção Thamnoxys formaram alguns subclados consistentes e a seção Foliosae se mostrou proximamente relacionada com a seção Thamnoxys. Os estudos taxonômicos foram baseados em aproximadamente 2000 exsicatas oriundas de herbários e coletas próprias. No Brasil ocorrem 18 espécies de Oxalis sect. Thamnoxys, diferenciadas principalmente por caracteres vegetativos relacionados à presença de xilopódio, forma, quantidade e distribuição dos folíolos e indumento e o caráter reprodutivo coloração da corola. Foram propostas as sinonimizações de quatro variedades e uma forma. O estudo da microestrutura da testa das sementes foi realizado através de microscopia eletrônica de varredura (MEV). A testa das sementes apresentou cinco tipos de esculturas: foveolada, costado-transversal, costado-longitudinal, fendido-costada e fendido longitudinalmente, que refletem, em parte, a classificação infragenérica de Oxalis.

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.