Nearly 4,000 species of fungi, including lichen-forming species have been recorded from Malaysia. Of the two fungal groups with the largest number of species in Malaysia, the Ascomycota and their asexual states have been surveyed in some habitats (decaying wood, marine and freshwater ecosystems, as parasites of some plants, and as agents of biodegradation), but have not been or have been only poorly surveyed in other habitats (as endobionts, in soils, on dung, as human and animal pathogens); the Basidiomycota are only partly surveyed: bracket fungi, and mushrooms and toadstools have been studied, but Malaysian rust and smut fungi remain very poorly known. Without doubt, many more fungal species in Malaysia have not yet been recorded, and it is likely that many of those, when found, will be new to science.