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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.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Zygophyllum orbiculatum Welwitsch ex Oliv. from Angola and Zygophyllum stapffii Schinz from Namibia were described in the late 1800’s. Recent comparisons of these two species revealed that they were morphologically very similar except that Zygophyllum orbiculatum has unifoliolate leaves and Zygophyllum stapffii has bifoliolate leaves. The similarity of these two species was investigated using nuclear ITS (Internal Transcribed Spacer, i.e. ITS1, 5.8SrDNA, ITS2) region sequence data as phylogenetic markers. Due to almost identical sequences and phylogenetic grouping, it was concluded that they were conspecific. However, the phylogenetic relationships of the major groups within the subfamily Zygophylloideae based on ITS sequences, were unresolved and unsupported, as was found in previous studies using chloroplast gene marker sequences. To resolve the phylogenetic relationships of the major groups within the subfamily Zygophylloideae, a next generation sequencing (NGS) approach was taken. Chloroplasts of taxa representing the major groups within the subfamily were isolated and chloroplast genome sequence data were generated using the Ion Torrent™ sequencer. Additional nuclear ITS cassette data (18SrDNA, ITS1, 5.8SrDNA, ITS2, 26SrDNA) were generated as a by-product and used to produce a large combined aligned sequence matrix for phylogenetic analysis. Model-based phylogenetic programs were able to retrieve strongly supported and resolved phylogenetic relationships of the major groups within Zygophylloideae. Two basal groupings were retrieved in the subfamily. The first grouping consisted of the genera Tetraena, Fagonia and Melocarpum. The second grouping consisted of the monotypic genus Augea and Zygophyllum orbiculatum/stapffii which were embedded within the genus Roepera. Using a gene duplication approach, the chloroplast marker data of genus Zygophyllum sensu stricto placed this genus basal to the Augea, Zygophyllum orbiculatum/stapffii, Roepera clade whilst the nuclear marker data of Zygophyllum sensu stricto, was found in a basal position to the entire subfamily. From this it is concluded that Zygophyllum sensu stricto shows evidence of incomplete lineage sorting. A revised taxonomy for the entire subfamily Zygophylloideae is proposed. / AFRIKAANSE OPSOMMING: Zygophyllum orbiculatum Welwitsch ex Oliv. uit Angola en Zygophyllum stapffii Schinz van Namibië is in die laat 1800's beskryf. Onlangse vergelykings van hierdie twee spesies het getoon dat hulle morfologies baie eners is, behalwe dat Zygophyllum orbiculatum unifoliolate blare besit en dat Zygophyllum stapffii bifoliolate blare besit. Hierdie ooreenkoms is ondersoek, met behulp van die nukleêre “ITS” (Internal Transcribed Spacer d.w.s. ITS1, 5.8SrDNA, ITS2) DNS-strook volgordedata as filogenetiese merkers. As gevolg van feitlik identiese geenopeenvolgings is bevind dat die twee spesies konspesifiek is. Die filogenetiese verwantskappe van die groot binnegroepe van die subfamilie Zygophylloideae, gebaseer op ITS geenopeenvolgings, was egter onopgelos en nie ondersteun nie, net soos in vorige studies waarin chloroplast geenmerkervolgordes gebruik was. Om die filogenetiese verwantskappe van die groot binnegroepe van die subfamilie Zygophylloideae op te los, was ‘n betreklik nuwe DNS volgordebepalingstegniek, naamlik “Next Generation Sequencing” (NGS), gebruik. Chloroplaste van taksa, wat die groot groepe binne-in die subfamilie verteenwoordig, is geïsoleer en chloroplast genoomdata is gegenereer met behulp van die Ion Torrent ™ (NGS) DNS-volgordebepaler. Bykomend was die nukleêre “ITS”-kasset volgordedata (18SrDNS, ITS1, 5.8SrDNS, ITS2, 26SrDNS) ook as 'n by-produk gegenereer en ook gebruik om 'n groot gesamentlike DNS oplyningmatriks vir filogenetiese doeleindes. Model-gebaseerde filogenetiese programme was in staat was om sterk ondersteuning en opgeloste filogenetiese verwantskappe van die groot groepe binne-in Zygophylloideae te ontravel. Die subfamilier toon twee basale groeperinge. Die eerste groepering bestaan uit die genera Tetraena, Fagonia en Melocarpum. Die tweede groepering bestaan uit die monotipiese genus Augea en Zygophyllum orbiculatum/stapffii, wat ingebed is binne-in die genus Roepera. Deur ‘n geendupliseringsbenadering te gebruik op die DNS geenopeenvolgings van die verteenwoordigende takson van Zygophyllum sensu stricto, is bevind dat die chloroplast DNS volgordes hierdie groep basaal aan ‘n Roepera/Augea/Zygophyllum orbiculatum/stapffii klade plaas, terwyl die nukleêre DNS volgordes hierdie groep basaal aan die hele subfamilie Zygophylloideae plaas. Hieruit is die gevolgtrekking gemaak dat Zygophyllum sensu scricto bewyse van onvolledige afstammelingsortering toon. ‘n Gewysigde taksonomie vir die hele subfamilie Zygophylloideae word voorgestel.

Thesis (M.Sc.(Systematics and Biodiversity Science))-- Stellenbosch University, 2001. / ENGLISH ABSTRACT: Sequence data from the intron and the spacer of the trnL-F chloroplast DNA region were used to study the phylogenetic relationships of the genus Zygophyllum L. (Zygophylloideae: Zygophyllaceae) in the southern African region. The chloroplast DNA was extracted from both herbarium and silica-gel dried material. Closely related genera, i.e. Augea Thunb., Fagonia L. and Tetraena Maxim. within the subfamily Zygophylloideae and more distantly related genera Seetzenia R.Br. ex Decne and Tribulus L. were used as outgroups. Sequences revealed length variation mainly due to the presence of indels (insertions and deletions). Phylogenetic analysis using parsimony revealed two distinct lineages for southern African members of Zygophyllum, corresponding to the proposed subgeneric classification (Van Huysteen 1937; Van Zyl 2000). There is a strong monophyly support for the sections within the subgenus Agrophyllum (Neck.) Endl. However, the transference of the monotypic section Grandifolia Engl. from subgenus Zygophyllum to Agrophyllum is not confirmed, because material of Z. stapffii Schinz. was not available. Despite the morphological evidence for the subdivision of the subgenus Zygophyllum, the molecular data did not confirm the monophyly for its sections. This could be the result of biased sampling, since all the species used in the analyses, except Z. cordifolium L.f. and Z. morgsana L., belong to section Capensia Engl. The trnL region data support the transfer of the mono typic section Morgsana Huysst. from subgenus Agrophyllum to subgenus Zygophyllum. The molecular data also seem to have implications for the biogeography of Zygophyllum. The southern African Agrophyllum representatives are related to East African and Middle East Zygophyllum species, whereas the southern African subgenus Zygophyllum members are closely related to Australian Zygophyllum species. / AFRIKAANSE OPSOMMING: Die volgorde-data van die trnL-F chloroplas-DNA gebied is gebruik om die filogenetiese verwantskappe van die genus Zygophyllum L. (Zygophylloideae: Zygophyllaceae) in suider Afrika te bestudeer. Die chloroplas-DNA is geëkstraheer van beide herbaria en silica-gel gedroogde materiaal. Naverwante genera binne die subfamilie Zygophylloideae bv. Augea Thunb., Fagonia L. en Tetraena Maxim., sowel as verder verwante genera, soos Seetzenia R.Br. ex Decne en Tribulus L., was as buite-groepe gebruik. Die lengte-variasie in die volgorde-data kan toegeskryf word aan indels (insertions and deletions). Filogenetiese analise deur die gebruik van parsimonie het twee duidelike ontwikkelingslyne vir suider-Afrikaanse Zygophyllum taksa aangedui. Dit stem goed ooreen met die voorgestelde subgeneriese klassifikasiesisteem vir die genus (Van Huysteen1937; Van Zyl 2000). Daar is 'n sterk ondersteuning vir monofilie van die seksies binne die subgenus Agrophyllum (Neck.) Endl. Die oorplasing van die monotipiese seksie Grandifolia Engl. vanaf subgenus Zygophyllum na subgenus Agrophyllum is nie bevestig nie, want materiaal van Z. stapffii Schinz. was nie beskikbaar nie. Ten spyte van morfologiese bewyse vir die subdivisie van die subgenus Zygophyllum het die molekulêre data nie die monofilie van die seksies bevestig nie. Dit is moontlik as gevolg van eensydige data-insameling, aangesien al die spesies wat in die analise gebruik word (behalwe Z. cordifolium L.f. en Z. morgsana L.) aan die seksie Capensia Engl. behoort. Die trnL-gebied data ondersteun die oordra van die monotipiese seksie Morgsana Huysst. van die subgenus Agrophyllum na die subgenus Zygophyllum. Die molekulêre data bied ode inligting oor die biogeografie van Zygophyllum. Die suider-Afrikaanse Agrophyllum taksa is verwant aan Oos-Afrika en Midde-Oosterse Zygophyllum spesies, terwyl lede van die Suid-Afrikaanse subgenus Zygophyllum nouverwant is aan Zygophyllum spesies in Australië.