851 
Advances in systematic knowledge 
of Australian Loranthaceae and Viscaceae: 
a review 
Bryan A. Barlow 
Abstract 
Barlow, Bryan A. (Australian National Herbarium, CSIRO Division of Plant Industry, GPO Box 
1600, Canberra, ACT 2601, Australia) 1996. Advances in systematic knowledge of Australian 
Loranthaceae and Viscaceae: a review. Telopea 6(4): 851-862. Better understanding of taxonomy 
and relationships of Australian Loranthaceae and Viscaceae has contributed significantly to 
views on endemism and migration in these families and in the Australian flora generally. 
Introduction 
When they are broadly defined as perennial aerial parasitic angiosperms attached to 
tree branches, almost all mistletoes in Australia belong to the families Loranthaceae 
and Viscaceae. Because of the unusual and very interesting biology of these 
plants, they have become a model group for a broad range of studies, encompassing 
host-parasite physiology, host-parasite co-adaptation, dispersibility and biogeography. 
Over the last 40 years systematic knowledge of Loranthaceae and Viscaceae has 
advanced greatly, in parallel with advances in knowledge of mistletoe biology. Lawrie 
Johnson has maintained a long interest in these plants, and through his herbarium 
work has contributed to the framework of our present systematic knowledge of them. 
Taxonomy of Australian Loranthaceae and Viscaceae — overview 
Over the last century the taxonomic history of Loranthaceae and Viscaceae has 
been exceedingly turbulent. It has led to the accumulation of a very large number of 
names now placed in synonymy, and to very complex tasks of systematic and 
taxonomic resolution. 
Since Lawrie Johnson first became interested in mistletoes, even their family status 
has changed. Until about 1970, Loranthaceae and Viscaceae were generally treated 
as subfamilies of a single family Loranthaceae. Significant differences in embryology 
(Maheshwari et al. 1957), karyology (Barlow 1963) and morphology (Kuijt 1968) 
provided strong evidence for their restoration as distinct families, as earlier proposed 
by Batsch (1802), Miers (1851) and Agardh (1858). Contemporary students of higher- 
level angiosperm classification all accepted their status as distinct families (Thorne 
1976, Takhtajan 1980, Dahlgren 1980, Cronquist 1981). On morphological grounds 
there are reasonable arguments that the families are not even directly related (Kuijt 
1968, 1969). Kuijt (1968) also segregated a third family Eremolepidaceae (not in 
Australia) from Viscaceae. 
In early taxonomic inventories, most species were referred to two large genera, Loranthus 
and Viscutn. This was the situation when the first floras of Australia (Bentham 1867) 
and the various States were prepared. However in many papers, mostly published 
