Peltigera Membranacea, Membranous Dog-Lichen

Day 84: A member of the family of Peltigeras, Membranous Dog-Lichen is cousin to a number of species commonly found in the wet forests of the Pacific Northwest. All are characterized with apothecia which, to this observer at least, resemble distorted fingernails. These are the fruiting bodies of a lichen, generating spores when the organism reaches maturity. If you were to turn over the olive-brown "leaves" (technically, the foliose thallus), you would find their backs covered with thread-like "teeth" called rhizines. Closer investigation with a magnifying lens would reveal a velvety covering (tomentosum) on the upper surface of the thallus. The woolliness of the tomentosum can be used to distinguish Peltigera membranacea from Peltigera canina in the field (P. canina's is fuzzier). Membranous Dog-Lichen is one of the most common Peltigeras in northwestern forests.