Abstract
As currently understood, the Lejeuneaceae flora of Australia consists of 122 species in 27 genera. The family occurs almost exclusively in rainforested areas along the eastern coast of the continent. Based on species composition, three floristic regions are recognized: tropical, subtropical and temperate. The tropical region contains 80 percent of the total number of Lejeuneaceae found in Australia, the subtropical region contains 45 percent, and the temperate region only 15 percent of the total flora. The affinities of the Lejeuneaceae in the tropical and subtropical regions are strongest with the Asian flora, and those of the temperate region are strongest with the New Zealand flora. The diversity of the Lejeuneaceae flora in Australia is higher than might be expected for a non-equatorial region. This diversity may result from the wide variety of rainforest habitats that are available along both latitudinal and altitudinal gradients. The temperate flora is probably derived from that which existed in Australia, New Zealand, Antarctica and probably southern South America prior to the breakup of Gondwanaland. The modern tropical flora is probably a mixture of species that were part of the original northern Gondwanan flora and those that have invaded more recently.