On the distribution of gymnosperm genera, their areas of endemism and cladistic biogeography

Abstract

A distributional analysis of 81 gymnosperm genera was undertaken. On the basis of the congruence in the distribution of these genera, nine areas of endemism were recognised. Many of these areas also represent areas of endemism for other plant and animal taxa. South-western China and New Caledonia are particularly interesting from the viewpoint of gymnosperm diversity and endemism. The suggested areas of endemism agree in part with some floristic regions previously proposed. The congruence between the areas of endemism suggested and postulated Pleistocene refuges and panbiogeographic nodes is discussed. A cladistic biogeographic analysis was carried out and a general area cladogram obtained by strict consensus shows two major components, one Gondwanic and the other almost Laurasian. This cladogram was compared with previous studies and the similarities and differences among relationship areas are discussed.