Nothofagus, Key Genus in Plant Geography

Abstract

The genus Nothofagus is the only representative of the Nothofagaceae. It comprises 36 species distributed in disjunct territories of the southern hemisphere: southern South America, New Zealand, East Australia, New Caledonia and New Guinea. This southern distribution pattern, together with the rich fossil record that is also found in Antarctica, sustains the status of the genus as a "key genus" in plant geography. The evolution of the genus is discussed, confronting different visions, and. integrating the phylogeny of related genera, such as the fungi species of the genus Cyttaria.Nothofagus has been considered as a "key genus" in plant geography (Darlington 1965; Van Steenis 1971) for at least three reasons: (1) because of the characteristic disjunct pattern of its species between South America and Australasia, together with the dominant character of these species in their territories of occurrence (Donoso 1993; Veblen et al. 1996) (Fig. 9.1); (2) because of its abundant fossil record, expressed in a rich array of macro and microfossils found in the southern territories including Antarctica (Dettmann et al. 1990); and (3) because the use of the genus as a model for testing different biogeographic methods and the various contesting visions that different studies have reached (Humphries 1981; Heads 1985, Linder and Crisp 1995, Cook and Crisp 2005; Knapp et al. 2005).