Peltigera membranacea is a species of lichenized fungus in the family Peltigeraceae. It has a foliose growth pattern, with what appear to be veins in the leaf-like parts, but these do not have a vascular function. The apothecia are erect, numerous, and often a bright brown-orange in colour.[1] Some simple sequence repeat markers have been developed for both the fungal partner (mycobiont) of Peltigera membranacea and its Nostoc photobiont partner; these allow for both population genetic studies and an alternative means of identifying between P. membranacea and its lookalikes.