Bachelor of Science, University Pretoria, Gauteng, South Africa, 1970. Master of Science, University Pretoria, 1977. Doctor of Philosophy, University Pretoria, 1988.
Schweickerdt herbarium curator University Pretoria, 1972—1977, research officer, 1978—1999, professor botany, since 2001. Advisory board University of South Africa Exxaro Chair Business & Climate Change, Pretoria, since 2008.
Member of South African Association Botanists (board member since 2008).
Married Noel Van Rooyen, October 7, 1978. Children: Eugene, Riaan, Leon.