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Telopea Vol. 6(4): 1996 
Secondly, my intensive and extensive study of Loranthaceae and Viscaceae of the 
southeast Asian region (Barlow 1974, 1993) has led to some refinement of generic 
limits, especially in Loranthaceae. This has resulted in a modest increase in the 
number of genera recognized in Australia. 
The most significant advances in knowledge have been in the Loranthaceae. When 
Lawrie Johnson implemented Danser's revisions for Australia, the known Australian 
Loranthaceae (sens, sir.) comprised 49 species in 8 genera. The family in Australia is 
currently estimated to comprise 74 species in 12 genera (excluding Norfolk Island). 
Because of the state of knowledge of the family, it now provides a good basis for 
analyses of flora evolution and historical biogeography, and it has contributed 
significantly to understanding these processes in Australia. These aspects of mistletoe 
biology are discussed below. 
Loranthaceae — another old southern family 
The Gondwanan affinities of the Australian flora are now widely documented. Many 
plant families and genera have been shown to have distributions and patterns of 
differentiation which are consistent with early development in Gondwana, and with 
subsequent dispersal on the fragments produced by the Gondwanan breakup. Studies 
by Johnson and Briggs (1975; 1981) made an important contribution to understanding 
the implications of these events for the differentiation of the Australian flora. They 
showed that major Australian families such as Myrtaceae, Proteaceae and Restionaceae 
have complementary patterns of relationship across the lands of the southern 
hemisphere, consistent with the geophysical history of Gondwana. 
The Loranthaceae are another group with a classical conformity with this pattern. 
Through detailed studies of cytogeography and comparative morphology (Barlow 
and Wiens 1971; Barlow 1981a, 1990), the family has become a model group for 
illustrating aspects both of the differentiation of Gondwanan floras in the southern 
lands, and also of the integration of the component elements of the Australian flora 
through Tertiary time. 
A feature of the Loranthaceae in Australia is that they strikingly illustrate the extent 
of integration of the Gondwanan and Intrusive Elements (Nelson 1981; Barlow 1981b) 
of the flora. The most obvious Gondwanan genera are the small temperate ones with 
many plesiomorphic character states (Atkinsonia, x = 12; Nuytsia, x = 12; Muclleritta; 
X = 11). They show relationships with other small genera of New Zealand and 
temperate South America, and apparently are relicts of the ancestral stock which 
differentiated in Gondwana. 
The other loranth genera in Australia which apparently belong to the Gondwanan 
element are Cecarria, Dactyliophora, Amyema and Diplatia. They all share a genome of 
X = 9 with large chromosomes, which is a derived state in the family. They are more 
tropical in their habitat requirements than the group mentioned above. Indeed, 
Cecarria, Dactyliophora and probably Amyema are centred in New Guinea. These genera 
have presumably differentiated on the Australian plate and, following the Miocene 
contact with the Sunda plate, have made limited intrusions to the northwest and 
into the Pacific. Amyema reaches mainland Asia and Samoa (see below). 
Cecarria, Dactyliophora and Diplatia are all small genera (1-3 species). Amyema is the 
largest genus in the region, with 92 species, of which 39 occur in Australia, 28 in 
New Guinea, and 34 elsewhere in Malesia. Dactyliophora and Diplatia are closely 
related to Amyema, and are undoubtedly part of the same evolutionary radiation and 
speciation event. In Australia Amyema and Diplatia species show strong integration 
