Volume 58A of the Flora of Australia series is the third volume dealing with the lichens. It includes descriptions of some of the more robust and luxuriant lichens of cool-temperate south-eastern Australia (Lobariaceae and Sphaerophoraceae), as well as ecologically important soil-inhabiting groups in semi-arid and arid regions (Peltulaceae, Endocarpon and Placidium). Also in this volume are the first Flora of Australia treatments of crustose lichens and the Trichotheliaceae, a family that is most diverse on the bark and leaves of trees and shrubs in tropical rainforest. Complete or partial accounts of seven orders are provided, including nine families, 24 genera and 256 species and infra-specific taxa. Descriptions and discussion are supplemented by important references, synonomy, and information on type collections, chemistry, distribution, habitat and published illustrations.