Cryptic, overlooked and undiscovered: Challenges of assessing the species richness of rust fungi in the tropics – and elsewhere

Institut für Pflanzenwissenschaften, Holteigasse 6, A-8010 Graz. 

5000–7000 species of rust fungi, the Uredinales, have presumably been described until today. Some 20000–30000 may still await discovery if we believe in extrapolations based on rust-host-ratios calculated in well-studied regions of the world. In this talk, the components of our ignorance will be addressed in the light of recent research on South American, Southern African and Australian rust fungi. It will be shown that – as expected – many species remain to be discovered in the field, but that an equal proportion of overlooked species slumbers in the world’s mycological collections ready to be unearthed by the eager, yet more sessile mycologist