1. Institute of Botany, Academy of Sciences of the Czech Republic; CZ-252 43 Pruhonice Czech Republic.
2. Institute for Plant Conservation, Botany Department; University of Cape Town; Rondebosch 7701 South Africa.
3. Section of Evolution and Ecology, University of California; Davis, California 95616 U.S.A.
4. Section of Plant Biology, University of California; Davis, California 95616 U.S.A.
5. Department of Biology, University of York; York YO10 5DD U.K.