Biogeographical patterns observed in floras are the result of a number of historical factors.
Biogeographers have viewed tectonic events as significant historical factors influencing patterns of species richness, endemism, and biotic history based on phylogenetic analyses. In many cases, biogeographers consider tectonic events in the context of major plate movements resulting in continental separation, convergence and generalized orogenic events. In particular, plant evolution and floras of South America have been strongly influenced by tectonic events on several scales. Microplate movements have played a significant role in the continental evolution of both the northern and southern margins of the continent. Hot spots and their associated aseismic ridges have also influenced the development of floras on both the eastern and western margins of South America.