Squamaria

Squamaria is a genus of lichens. Lichens are composite organisms that arise from algae or cyanobacteria living among filaments of multiple fungi in a mutualistic relationship. Squamaria lichens are typically found on rocks, particularly limestone. They are characterized by their squamulose thallus, which means the thallus is made up of small, scale-like lobes. The color of Squamaria species can vary, often appearing gray, greenish-gray, or even yellowish.

The reproductive structures of Squamaria, known as apothecia, are usually disc-shaped and can be the same color as the thallus or darker. The specific species within the Squamaria genus are distinguished by their microscopic features, chemical compounds, and geographic distribution. For example, Squamaria saxicola is a widely distributed species found in many parts of the world.

Historically, the classification of lichens has undergone revisions, and some species previously placed in Squamaria may now be assigned to other genera based on updated phylogenetic studies. However, the term "squamaria" often evokes the characteristic squamulose form of these rock-dwelling lichens. Their presence can be an indicator of air quality, as many lichen species are sensitive to pollution.