[1] Univ Venda, Dept Bot, Univ Rd, ZA-0950 Thohoyandou, South Africa
[2] South African Natl Biodivers Inst, Compton Herbarium, Private Bag X7, ZA-7735 Claremont, South Africa
[3] Univ KwaZulu Natal, Sch Life Sci, Res Ctr Plant Growth & Dev, Private Bag X01, ZA-3209 Pietermaritzburg, Scottsville, South Africa