Common Boulder Lichen

The common boulder lichen (<em>Porpidia macrocarpa</em>) is a crustose lichen species with a wide distribution across Europe and the Americas, recorded in Colombia, Denmark, Norway, Portugal, Sweden, and the United States. This species typically inhabits siliceous rock surfaces in a variety of exposed terrestrial environments across both North and South America and Europe. The common boulder lichen is classified as Near Threatened on the IUCN Red List, suggesting that its populations face potential pressures and require monitoring. As a slow-growing crustose lichen, it often colonizes hard rock substrates including granite and quartzite, forming a close symbiotic relationship between its fungal and algal components. It plays an important role in the early stages of soil formation through the gradual weathering of rock surfaces. Biological traits of this species remain poorly documented in the scientific literature.