Notes on the origins of Australian desert vines

Data from six Australian deserts show that 25 genera of vines are present. Fourteen genera are likely to be from rainforest stock and a further two can be found in seral stages of rainforest. Of the other genera, two are Australian endemics from areas of Mediterranean climate, three are dry-country succulents, three are widespread temperate to tropical Fabaceae, and Convolvulus L. is cosmopolitan. Of the 37 species represented, 10 can be found in dry or monsoon rainforest at present. As many as 59% of the species are from, or likely to be derived from, rainforest lineages. Adaptation to increasing aridity by the aseasonal wet rainforests of the Early Tertiary led to the development of seasonally dry rainforests by the mid-Tertiary. Subsequently, in the face of greater aridity, some dry rainforest lineages have produced species capable of surviving desert conditions, the most obvious adaptation being reduction in leaf area. Evolution of some of the dry-country succulent vines may be more recent, involving pre-adapted immigrant taxa.