Lichenicolous fungus
A Lichenicolous fungus is a parasitic fungus that only lives on lichens as the host.[1] A lichenicolous fungus is not the same as the fungus that is the component of the lichen, which is known as a lichenized fungus.[citation needed] They are most commonly specific to a given fungus as the host, but they also include a wide range of pathogens, saprotrophs, and commensals.[1] It is estimated there are 3000 species of lichenolous fungi.[2] More than 1800 species are already described among the Ascomycota and Basidiomycota.[2] More than 95% of lichenicolous fungi described as of 2003 are ascomycetes, in 7 classes and 19 orders.[1] Although Basidiomyces has less than 5% of lichenicolous lichen species, they represent 4 classes and 8 orders.[2] Many lichenicolous species have yet to be assigned a phylogenetic position as of 2003.[1]