Biogeographical relationships of Australia and Malesia: Loranthaceae as a model

Summary

Major interdigitation of an autochthonous Australian and a Malesian flora occurred in New Guinea and northern Australia in late Tertiary and Quaternary time, when the isolation of the two floras was weakened by geophysical and climatic events. In Australia this interaction had been preceded by early differentiation of warm and cool and of moist and dry rain forest elements from a mesic pan-Gondwanan flora, and of open forest and heathland vegetation in response to edaphic evolution. However, there is a growing perception that even in the Malesian flora there are ancient links to an early Gondwanan flora, perhaps involving India and parts of southeast Asia as Gondwanan fragments. Throughout these changes many primitive Gondwanan elements have survived in durable refugia in northeastern and eastern Australia. Thus in Australia there has developed an intricate pattern of humid forest communities which differ in composition, age, endemism, relictuality and richness. In the mistletoe family Loranthaceae, which is a classic austral group, there are various biogeographic patterns which are consistent with the suggested episodes in the development of the Australasian-Malesian flora. These are described as examples to illustrate the possible vegetation history.