(chemistry) An organic acid, C₁₄H₂₄O₃, obtained from Iceland moss. / (chemistry, obsolete) fumaric acid

Rhizocarpon geographicum, a lichen that grows in patches on rocks in mountainous areas, giving the appearance of a map.

A disease of the skin and/or mucous membranes, resulting in a lichenoid appearance.

Synonym of old man's beard (lichen of genus Usnea)

A crustose lichen with small upward-pointing fruiting bodies supposed to resemble dressmakers' pins. They include members of the genera Calicium and Chaenotheca.

Letharia vulpina, a bright yellow-green, shrubby, fruticose lichenized species of fungus in the family Parmeliaceae.

The disease lichen planus.

Any of the genus Cladonia of moss-like lichens.

(medicine) A chronic inflammatory skin disease, often affecting the genitals.