The Loranthaceae is the largest flowering-plant family with aerial, branch parasites. Of the 76 genera, three are terrestrial root parasites and are considered primitive in the family. The remaining 73 genera are shrubby, aerial parasites found within the forest canopy. We have been studying the Loranthaceae with an emphasis on comparative morphology and evolution of the haustorial system. To date we have collected seedlings, representative haustoria and DNA samples from more than 50 genera. Collections represent four Gondwanan landmasses that are currently geographical areas of high species diversity for the family. Hypotheses of haustorial evolution propose that aerial parasites evolved from vining, root parasitic forms and that the occurrence of epicortical roots is primitive while an endophytic system comprised of bark strands is advanced. Our data are used to test aspects of these hypotheses and correlate haustorial type with ecological change.

Key words: Gondwana, haustorium, Loranthaceae, parasitic angiosperms