views updated

Pertusariales (subdivision Ascomycotina) An order of fungi which includes crustose lichens and saprotrophic and lichenicolous fungi. Apothecia are sessile or immersed; they may have open discs or may be closed and perithecium-like. Asci are thick-walled; the spores are large. Species are found on various types of substrate, but rarely on limestone.