Teloschistales and parmeliaceae a review of the present problems and challenges in lichen systematics at different taxonomic levels

Problems in classifications of main systematic groups are discussed for lichenized ascomycetes exemplified mainly with the Teloschistaceae and Parmeliaceae. Different criteria for delimiting genera and species in these two families are discussed. The lack of separating infraspecific taxa for assigning evolutionary divergence is obvious in both families. The subspecific category is rarely used in lichen systematics.