Plant communities on desert to montane transects in the mediterranean type climatic areas in southern California, central Chile and the Cape, South Africa have been analysed to determine the extent of vegetation convergence. Data on floristic richness, growth form, leaf duration, leaf size, and spineseence, of the woody plants, collected by Parsons & Moldenke (1975) from analogous climatic sites in California and Chile, were compared with data from analogous sites in the Cape. Considerable convergence in vegetation structure between floristically distinct but climatically similar sites in California and Chile has been demonstrated by Parsons & Moldenke (1975). Cape vegetation, however, shows little convergence to these mediterranean regions. In Cape desert communities succulence rather than drought deciduousness is the principal adaptive strategy. Cape fynbos communities show major differences from communities at analogous sites on the other continents. Much of the divergence between fynbos and the vegetation of the other continents can be attributed to the nutrient-poor soils on which fynbos has evolved.
Keywords California - Cape Province - Chile - Convergence - Edaphic factors - Mediterranean climate - South Africa - Speeies richness - Vegetation structure
We thank Mr. F.J. Kruger for help with pre-project planning, Ms. E. Esterhuysen for aid with identifications, D.J. Parsons for unpublished data, and H.W. Bond, H.P. Linder, H.A. Mooney, D.J. Parsons, R.K. Peet, P.H. Raven, J.C. Scheepers, H.C. Taylor, R.H. Whittaker, and an anonymous reviewer for comments on the manuscript. This work was supported by a C.S.I.R. post-graduate grant (R. Cowling), the Fynbos Biome Environmental Project and the Botanical Research Institute.