Causes of plant species rarity in semi-arid southern Australia

The ecology of 17 species of angiosperms rare in semi-arid Victoria is briefly described. Five species are pioneers after fire or clearing, two occur after flooding and one appears to require a period of exceptionally high rainfall. The rarity of the remainder may be partly due to palatability to grazing animals for some and restriction to gypseous soils for others. Cases of rarity where occurrence is related to clearing, fire, high rainfall or floods are described and the erratic nature of such events in the area dealt with. The likely dependence of these species on long-term survival of soil-stored seed is stressed.