Study of Plants

The Botany Department became an independent Department in 1981. The main focus of the Department is the extension of the Herbarium. The term Herbarium was first used by Tournefort in 1700 to describe a collection of dried plants. Such a collection is ordered and arranged according to a specific classification system and is used for identification, classification and nomenclature of plant taxa. The Herbarium at the National Museum (NMB) is internationally accredited. Research efforts currently concentrate on the sustainable utilisation of medicinal plants of South Africa.


Postdoctoral Fellow appointed

Madeleen Struwig

23 January 2017
Dr Madeleen Struwig joined the Botany Department in January 2017 as a Postdoctoral Fellow for two years.  She will be conducting a taxonomic revision on two genera within the Aizoaceae, commonly known as the “vygie” family.  The Aizoaceae is a large family of succulent plants that are mainly distributed in the winter rainfall area of southern Africa.  The genera on which she will be working are however, distributed within central South Africa.  She will also be part of the team that will do a survey on the use of medicinal plants by the people of the Ghaap plateau and the Riemvasmaak area.

Previous work of Dr Struwig included a taxonomic revision on Boerhavia and Commicarpus (Nyctaginaceae) in southern Africa, the taxonomy of the southern African Menispermaceae and the pollen morphology of Prototulbaghia.


Principal Museum Scientist and Head of Department

PC Zietsman PhD

Ziets-ZietsmanZiets obtained his BSc, BSc Hons and MSc at the University of Pretoria, majoring in Botany and Zoology. He researched biological nitrogen fixation at Nylsvley Nature Reserve for his Masters thesis. He obtained his PhD in Botany at the University of the Orange Free State in 1988. The title of his thesis is: Reproductive Biology of Ziziphus mucronata subsp. mucronata (Rhamnaceae). In 1983 he took up a post as Museum Scientist to be the first botanist employed at the Museum. In 2003 he obtained a Masters degree in Environmental Management from the University of the Free State. The title of this mini-thesis was: Sustainable harvesting of Devil’s Claw (Harpagophytum procumbens): A community based conservation approach. His main interest is the sustainable utilisation of medicinal plants and biodiversity. He is a Research Associate of the Centre for Environmental Management (CEM) at the University of the Free State. He is also a renowned nature and wildlife photographer.

Assistant Museum Scientist

Elmarie van Rensburg MSc

Elmarie NelElmarie obtained a BSc degree in Genetics, majoring in Botany and Genetics, and an Honours degree in Botany at the University of the Free State. She was appointed as Assistant Museum Scientist in the Botany Department in January 2011. Elmarie spent four months (November 2014 to February 2015) in Vienna, Austria, participating in an International Research Staff Exchange Scheme: hERG Related Risk Assessment of Botanicals. This was in collaboration with the Department of Chemistry at the University of the Free State. Medicinal plants from South Africa collected by the Botany Department were screened for hERG channel inhibition at the Department of Pharmacology and Toxicology, University of Vienna.

Elmarie graduated with an MSc in December 2016. The title of her thesis is: hERG channel inhibitors in South African medicinal plants with the focus on Boophone disticha (Amaryllidaceae) bulbs.

Louise-ZietsmanSenior Research Assistant

Louise Zietsman

Louise obtained her BSc (majoring in Botany and Zoology), BSc Hons (cum laude) and Higher Education Diploma at the University of Pretoria. She worked as Herbarium Assistant at the Museum from 1985–1986. She interrupted her career to attend to her family and after 16 years started working again, first at the University of the Free State in the Department of Soil, Crop and Climate Sciences and also at the Centre for Environmental Management. She returned to the Museum in November 2008 as Senior Research Assistant responsible for the collection.



Currently the focus area of research is the sustainable utilisation of indigenous medicinal plants, with much attention paid to the sustainable harvesting of Devil’s Claw (Harpagophytum procumbens). Previously a great deal of research was done on pollination biology.

Publications - Scientific Articles

Zietsman, P.C. & Botha, F.C. 1987. Seed germination of Ziziphus mucronata subsp. mucronataSouth African Journal of Botany 53(5): 341-344.

Zietsman, P.C., Grobbelaar, N. & Van Rooyen, N. 1988. Soil nitrogenase activity of the Nylsvley Nature Reserve. South African Journal of Botany 54(1): 21-27.

Zietsman, P.C., Van Wyk, A.E. & Botha, F.C. 1989. Vegetative and reproductive phenology of Ziziphus mucronata  subsp. mucronata (Rhamnaceae). South African Journal of Botany 55(6): 564-573.

Zietsman, P.C. 1990. Pollination of Ziziphus mucronata  subsp. mucronata (Rhamnaceae). South African Journal of Botany 56(3): 350-355.

Du Preez, P.J. & Zietsman, P.C. 1991. A unique locality for Oleandra distenta, the first recorded for the Orange Free State. Bothalia 21: 65-66.

Zietsman, P.C. 1991. Reproductive biology of Grewia occidentalis L. (Tiliaceae). South African Journal of Botany 57(6): 348-351.

Zietsman, P.C. & Botha, F.C. 1991. Flowering of Ziziphus mucronata  subsp. mucronata(Rhamnaceae): anthesis, pollination and protein synthesis. Bot. Bull. Academia Sinica 33: 33-42.

Zietsman, P.C., Du Preez, P.J. & Bezuidenhout, H. 1992. A preliminary checklist of flowering plants of the Vaalbos National Park. Koedoe 35: 1-10.

Zietsman, P.C. 1993. Pollination in Pelargonium dolomiticum Knuth (Geraniaceae). South African Journal of Botany 59(2): 259-264.

Zietsman, P.C. 1994. Autogamy in Sesamum triphyllum  var. triphyllum (Pedaliaceae). Navors. Nas. Mus., Bloemfontein 10(15): 633-646.

Loubser, J. & Zietsman, P.C. 1994. Rock painting of postulated Brunsvigia sp. (Amaryllidaceae) at Thaba Bosiu, western Lesotho. S.A. Jnl. Science 90: 611-612.

Zietsman, P.C. 1998. Pollination Biology of Cotyledon orbiculata L. var. dactylopsis Toelken (Crassulaceae). Navors. Nas. Mus., Bloemfontein 14(4): 81-96.

Zietsman, P.C. & Bezuidenhout, H. 1999. Flowering plant biodiversity of Augrabies Falls National Park: a comparison between Augrabies Falls National Park, Kalahari Gemsbok National Park, Vaalbos National Park and Goegap Nature Reserve. Koedoe 42: 95-112.

Smith, G.F., Zietsman, P.C., Steyn, E.M.A. & Breuer, I. 2000. Distribution of Haworthia venosa subsp. tessellata in Southern Africa. Haworthiad. 40-43.

Eksteen, D., Pretorius, J.C., Niewoudt, T.D. & Zietsman, P.C. 2001. Mycelial growth inhibition of plant pathogenic fungi by extracts of South African plant species. Annals of Applied Biology 139: 243-249. 

Pretorius, J.C., Magama, S. & Zietsman, P.C. 2003. Growth inhibition of plant pathogenic bacteria and fungi by extracts from selected South African plant species. South African Journal of Botany 69(2): 186-192.

Magama, S., Pretorius, J.C. & Zietsman, P.C. 2003. Antimicrobial properties of extracts from Euclea crispa subsp. crispa (Ebenaceae) towards human pathogens. South African Journal of Botany 69(2): 193-198.

Pretorius, J.C., Magama, S. & Zietsman, P.C. 2003. Purification and identification of antibacterial compounds from Euclea crispa subsp. crispa (Ebenaceae) leaves. South African Journal of Botany69(4): 579-586.

Zietsman, P.C. & Pelser, A. 2004. Sustainable harvesting of Devil’s Claw (Harpagophytum procumbens): A community based conservation approach. Navors. Nas. Mus., Bloemfontein 20(1):1-18.

Zietsman, P.C. Reproductive Biology of Stomatium mustellinum (Aizoaceae). Bothalia. In preparation.


The Botany Department works in close collaboration with various institutes:

  • South African National Biodiversity Institute (SANBI) – ongoing.
  • University of the Free State (UFS): Department of Organic Chemistry: Natural products, and the Centre for Environmental Management - ongoing.
  • Regional Trade and Facilitation Programme (RTFP) - completed 2009.
  • Council for Scientific and Industrial Research (CSIR) Resource assessment - completed 2009.
Services Offered

The Botany Department renders support services to the community by supplying information, education, plant identification and research.

Loan Policy

Material will be made available to bone fide research institutions, subject to the Herbarium’s loan conditions.

For enquiries contact Louise Zietsman

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