Peltigerales

Peltigerales is an order of lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. The taxonomy of the group has seen numerous changes; it was formerly often treated as a suborder of the order Lecanorales. It contains two suborders, eight families and about 45 genera such as Lobaria and Peltigera.

The fungi form lichens in a symbiotic relationship with one or two photosynthetic partners which may be a cyanobacterium such as Nostoc or a green alga such as Coccomyxa. The majority of species contain just a cyanobacterium, a smaller number have both a cyanobacterium and a green alga while only a few species have just a green alga. The thallus of the lichen may be foliose (leafy), subfruticose (somewhat shrubby) or granular-squamulose (scaly). The thallus attaches to a surface by means of small root-like rhizines. In some species, the thallus may vary in appearance depending on whether it contains a cyanobacterium or a green alga. Sometimes these different morphs of a single fungus were formerly thought to be separate species.