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A systematic revision of Zygophyllum (Zygophyllaceae) in the Southern African regionVan Zyl, Loretta 03 1900 (has links)
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.
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An assessment of the subgeneric classification of Zygophyllum (Zygophyllaceae) in Southern Africa : evidence from noncoding trnL-trnF chloroplast DNA sequencesMakwarela, Azwimpheleli M. 04 1900 (has links)
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.
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