The cushion plants of lowland southern Australia

摘要

A preliminary analysis has recorded the cushion lifeform in 60 taxa from lowland southern Australia (i.e. latitudes south of 26 degrees S) encompassing six morphological forms from open, non-peat-accumulating species (58 taxa) to hard, dense cushions more typical of alpine and subalpine areas (2 taxa). Only two species appear to be obligate cushions. All but six cushion-forming species are endemic to southern Western Australia. Most species occur in the Transitional Rainfall Zone rather than the High Rainfall Zone or the more and interior, with only one species being endemic to the and zone.In Western Australia cushion-forming species occur on exposed coasts, granites, edges of salt lakes and sandplains; almost half of the species also commonly occur across a number of other habitat types. The few plant communities dominated by cushion plants are generally restricted to small areas of a specific habitat type such as Borya herblands on shallow soils around outcropping granites. Lowland cushion species in Western Australia do not appear to be restricted to the most stressful habitats.