1. Babylonstoren Farm, Simondium, Western Cape, South Africa. Affiliate researcher and senior lecturer, University of the Western Cape, P. Bag X17, Bellville, 7535 South Africa, E-mail: ; Orcid id: https://orcid.org/0000-0003-0143-8090
2. Independent Researcher, P.O. Box 21168, Windhoek, Namibia; H.G.W.J. Schweickerdt Herbarium, Department of Plant and Soil Sciences, University of Pretoria, Pretoria, 0002 South Africa. E-mail: ; Orcid id: https://orcid.org/0000-0002-0181-3543
3. Royal Botanical Garden, Kew. E-mail: ; Orcid id: https://orcid.org/0000-0002-6052-6675.
4. Ongava Research Centre, Private Bag 12041, Windhoek, Namibia.
5. Biodiversity Research Centre, Department of Natural Resources Sciences, Namibia University of Science and Technology, Private Bag 13388, Windhoek, Namibia. E-mail: ; Orcid id: https://orcid.org/0000-0003-3383-7758
6. Departamento de Biologia da Faculdade de Ciências da Universidade Agostinho Neto, Av 4 de Fevereiro 71 6 andar, Luanda, Angola. E-mail: ; Orcid id: https://orcid.org/0000-0002-7812-5490.