The Water Factor and Convergent Evolution in Mediterranean-type Vegetation

Abstract

One of the classical observations in plant geography is the phenomenon of convergence of plant life forms in areas of similar climate. This convergence is perhaps most dramatic in the mediterranean 1-climatic areas of the world: the Mediterranean region proper, California, central Chile, southwest Africa and southwest Australia. All of these areas are characterized by a distinct climatic pattern with six months of cool, but not cold, winters with moderate rainfall followed by hot, dry summers. In response to this climate a similar vegetation occurs consisting of dense stands of shrubs and low trees with small, thick, evergreen leaves.