The fairy circles in Namibia are an intriguing andunexplained feature of the pro-Namib and northern parts ofSouth Africa. The presence of hundreds of almost circularpatches where no plants grow were first mentioned inscientific literature in 1971 and since then scientist havetried to find an explanation for the existence of thesecircles. Although there are many hypotheses regarding theorigin of these circles not one of these can explain theexistence of these circles satisfactory. In this study a fewdifferent aspects of the fairy circles were investigated tosearch for variations in biotic and abiotic factors in thecircles and in the areas between the circles. Total elementanalysis of the soil from the different microhabitats insidethe circle, on the edge of the circle and between the circles,referred to hereafter as the matrix and at different depths inthese microhabitats were performed by inductively coupledplasma mass spectrometry (ICP-MS) and analyzed byprinciple component analysis (PCA). No definite patternscould be detected regarding the concentration of theelements in the respective microhabitats. The occurrenceof vesicular arbuscular mycorrhiza (VAM) in the roots ofplants collected from the different microhabitats was alsoinvestigated. It was found that VAM occurred in the rootsfrom plants collected in the matrix and from the edge butno VAM was found in plants collected inside the circles.The succulent species Euphorbia damarana has beenimplicated as a reason for the circles and investigated todetermine the presence of germination inhibiting com-pounds. No such compounds were found. The crude extractof E. damarana was also tested for growth inhibition andfound to significantly reduce the growth of seedlings. Potexperiments with soil collected from the different micro-habitats were performed using the indigenous grass, Stipa-grostis uniplumis, as bioindicator. The plants from theseexperiments exhibited the same trend as those in nature,confirming the results of previous researchers who did thesame experiment using another grass species.

doi:10.1016/j.sajb.2007.02.163

Traditional non-wood uses of wild plants in central-northernNamibia

F.N. Kangombe, B.J. StrohbachNational Botanical Research Institute, Private Bag 13184,Windhoek, Namibia, South Africa

The specific aim of this study was to investigate thetraditional uses of non-woody plants in central-northernNamibia with particular emphasis on sustainable manage-ment and changes in the availability of these resources overthe years. The various wild plant species used for basketry,grazing, medicine, food, dyes, cosmetics, and culturalceremonies are included here. Informal interviews wereconducted with community members in Omanogondjamba

and Epyeshona villages of Omusati and Oshana Regionsrespectively. Traditionally, people in central-northern Nami-bia used a wide variety of plants for various purposes.However, a decline in both the availability of plant resourcesand the extent to which they are used, from early settlementtimes to present times is observed. This decline is mainlydue to increased agro-silvo-pastoralism, a poor land usesystem which has put the entire local environment undersevere pressure. The rapid population growth in the area,overgrazing and clearing of land for subsistence cropfarming together contribute to the observed scarcity andperhaps local extinction of some plant species within theregion. Potential commercialization of plant products such astraditionally made baskets and the oil of Citrulus lanatus isone possible factor posing a threat to the remaining plantresources. There is therefore an urgent need to develop andimplement a management plan that will ensure sustainableuse of plants as a valuable natural resource in central-northern Namibia.

doi:10.1016/j.sajb.2007.02.164

A taxonomic revision of the genus Pentatrichia (Asteraceae)

E.S. Klaassen, E.G. Kwembeya, E. MaassNational Botanical Research Institute, Private Bag 13184,Windhoek, Namibia, South Africa

A taxonomic revision of the genus Pentatrichia Klatt is herepresented. Morphological data from previously described taxa:P. alata S. Moore, P. avasmontana Merxm., P. petrosa Klattand P. rehmii (Merxm.) Merxm. were subjected to bothunivariate and multivariate statistical methods. Both herbariummaterial and voucher specimens collected during fieldworkwere examined. Morphological character data were analysed byUnweighted Pair-group Method Arithmetic Average (UPGMA)clustering algorithms so as to obtain groupings as objectively aspossible. This cluster analysis revealed the existence of threespecies in the genus namely: P. alata, P. petrosa and P. rehmii.Pentatrichia avasmontana Merxm. is reduced to subspecificlevel under P. rehmii (Merxm.) Merxm.; P. rehmii subsp.avasmontana (Merxm.) Klaassen and Kwembeya comb. nov.Two ordination methods, Principal Coordinate Analysis andPrincipal Component Analysis, were employed and confirmedthe results obtained from cluster analyses. Leaf characters andpresence/absence of ray florets proved to be the most importantcharacters in diagnosing species in the genus. Red Listassessments of all the species were undertaken. All speciesemerged as “Least Concern” with P. rehmii subsp. rehmiifalling in the “Vulnerable” category. This revision includes anew key for the species, descriptions and distribution maps atthe quarter degree level.

doi:10.1016/j.sajb.2007.02.165

329Abstracts