Matt H. Buys

A model for species-area relationships in plant communities

A model is proposed for the fitting of species-area curves to data from the Stellenbosch region, South Africa. Basic assumptions of the model are finiteness of the number of species in a finite area, and random distribution of plant species over the region. The model involves a distribution of densities of different species, and the parameters of this distri- bution are useful for describing and classifying communities. The data of the Stellenbosch region suggest that the assump- tions of the model break down in areas greater than 500 m2.

Boraginaceae cymes are exclusively scorpioid and not helicoid

Boraginaceae have erroneously been associated with helicoid cymes, when upon closer inspection they exclusively possess scorpioid cymes (cincinni). A discussion of the inflorescence structure in Boraginaceae is presented with the help of an overview of monochasial branching systems and a three-dimensional representation thereof. Reasons for the incorrect description of Boraginaceae inflorescences are also provided.

Ledebouria, Resnova and Drimiopsis : a tale of three genera

The monophyletic status of Ledebouria, Resnova and Drimiopsis (Hyacinthaceae) was investigated using cladistic analyses of morphological characters as well as by combined trnL-F and morphology dataset. Based on morphology alone, numerous synapomorphies support Ledebouria, Resnova and Drimiopsis as three separate clades. In contrast, trnL-F data in a reduced taxon sample suggest that Resnova and Drimiopsis are imbedded within Ledebouria, while in combination with morphology again suggest them to be separate. The analysis of morphological data shows that the majority of morphological characters listed by Manning & al. (2004) to support Ledebouria s.1. are homoplasious or symplesiomorphies. A revised taxonomy of Ledebouria, Resnova and Drimiopsis is premature.

The stigma and style of Lobostemon (Boraginaceae) and their systematic implications

A study of the stigma and style of Lobosfemon Lehm. (Boraginaceae, tribe Lithospermeae Bentham & Hooker) is presented. Lobostemon is endemic to the Cape fynbos region of South Africa and comprises about 29 species. Surface characters of the stigma as well as the indumentum of the styles are discussed. In this regard, Lobosfemon is characterised by possessing dry, papillate, bilobed stigma branches. Glabrous styles are largely confined to the section Lobostemon, A transformation series of the stigmatic regions investigated is presented.

Lobostemon daltonii (Boraginaceae): a new species from the Western Cape, South Africa

A new species of Lobostemon Lehm. (Boraginaceae), placed in the section Fruticosi Levyns, is described from Cape Infanta region in the Western Cape, South Africa. Illustrations of the macromorphology, indumentum, stigma and style, fruit as well as a distribution map, are provided.

Using the WORLDMAP PC program for measuring biodiversity in order to choose prioritized conservation areas in southern Africa

The various measures of biodiversity available on the W orldmap PC-program are discussed. Data on Mariscus Vahl (Cyperaceae) are used to illustrate these measures as well as to elucidate the choosing of prioritized conservation areas in southern Africa.

A provisional analysis of the Flora of Stellenbosch

The topography, hydrology, geology, soils as well as the climate of the study area are discussed and a map illustrating the boundaries of the area, is provided. Floristic relations between taxa in the Flora of Stellenbosch (FSTE) are examined and compared to those of other areas. Results indicate that the FSTE is richer in taxa than other areas of similar size. The FSTE in comparison with other areas, possesses the highest number of species per square kilometre. The ranking of families does not differ significantly in comparison to similar rankings for other comparable areas, except that the ranking of the Poaceae and Cyperaceae is significantly higher in the FSTE than for the Cape Flora. A systematic list of FSTE is presented as an appendix.

Optimised DNA isolation from Acacia karroo (Fabaceae)

The isolation of high quality DNA from Acacia karroo Hayne is impeded by the release of secondary metabolites. The isolation method of Bousquet et al. (1990) was modified to include numerous CTAB extractions coupled with an increased buffer to tissue ratio and the addition of 5 M NaCI, yielding high quality DNA.

Lectotypification of the Names of Linnaean Echium Species Now in Lobostemon (Boraginaceae)

The first species of Lobostemon Lehm. to be collected in South Africa were originally considered to belong to Echium L. Although Lobostemon was established by Lehmann (1830), it was Buek (1837) who placed the three Linnaean species in Lobostemon. To date their names have not been typified. A visit to herbaria (BM, L, LINN, S, UPS) housing possible Linnaean material was undertaken to account for all potential type material.