Best Saxicolous

Xanthoria elegans is an orange to reddish-orange foliose lichen that commonly grows on exposed rock in alpine, polar, and other cold environments. Its color is produced by protective pigments that help the lichen tolerate intense light, drying, and repeated freezing. Because colonies can expand slow...

Umbilicaria mammulata, commonly called smooth rock tripe, is a foliose lichen that attaches to exposed rock through a central point, giving the thallus an umbilicate form. It has broad, brown to dark brown plates with a comparatively smooth upper surface and a dark lower side. The species occurs on...

Placopsis gelida is a crustose lichen that grows on exposed siliceous rock, especially in cold alpine and Arctic environments. It forms a tightly attached thallus with pale or grayish areas and distinctive pink to reddish reproductive structures or cephalodia, depending on the stage and interpretati...

Parmelia saxatilis is a foliose lichen commonly known as crottle or salted shield lichen. It has gray, leaf-like lobes with a network of raised ridges and often grows attached to rocks, tree bark, and other exposed surfaces. The species has been used historically as a source of lichen dye, especiall...

Umbilicaria pustulata is a foliose lichen in the rock-tripe group, attached to exposed stone by a central holdfast rather than across its entire lower surface. Its brownish to gray thallus has blister-like pustules and broad lobes, and it occurs on rocks in mountainous, boreal, and other cool or ope...

Ochrolechia tartarea is a crustose lichen that grows on exposed rock surfaces, especially in cool and humid regions. It is historically associated with cudbear, a purple dye made from certain lichen species and formerly produced in Scotland and Scandinavia. The species is of interest both as a saxic...

Stereocaulon vesuvianum is a fruticose lichen associated with volcanic and other nutrient-poor rocky habitats. It develops a branched, grey to grey-white thallus with a cottony appearance and can grow on relatively recent lava surfaces. As a pioneer organism, it contributes to the early colonization...

Umbilicaria vellea is a foliose lichen in the genus Umbilicaria that grows attached to exposed rock. Its broad, leathery thallus is held to the substrate by a single central attachment point, a structure described as umbilicate and responsible for the common comparison with an umbrella. The species...

Ramalina siliquosa is a fruticose lichen that typically grows on exposed rocks and coastal cliffs, especially in Atlantic maritime environments. Its thallus forms tufts of flattened, strap-like branches that can become weathered and irregular with age. The species is useful for readers interested in...

Caloplaca marina is a saxicolous, crustose lichen associated with rocky marine shorelines. Its thallus can appear orange to yellow-orange, and the species is adapted to exposed coastal surfaces that receive salt spray and periodic wetting by seawater. It is of interest to lichen observers studying i...

Caloplaca aurantia is an orange crustose lichen that grows tightly attached to mineral surfaces, particularly sun-exposed calcareous rock. Its bright orange thallus and fruiting structures help distinguish it from less strongly pigmented crustose lichens, although accurate identification may require...

Umbilicaria muehlenbergii is a foliose rock lichen with an umbilicate thallus attached to the substrate by a central holdfast. It commonly grows on exposed rock surfaces, especially in North America, and develops gray to brown lobes with a textured upper surface. The species is useful for readers st...

Umbilicaria hyperborea is a foliose, rock-dwelling lichen in the genus Umbilicaria. Its thallus is attached to stone by a central holdfast and expands into dark, leathery lobes, a structure commonly described as umbilicate. It occurs in cold exposed environments, including Arctic and alpine habitats...

Placynthium nigrum is a distinctive cyanolichen recognized by its black, radiating rosettes of crinkled lobes, commonly found colonizing damp, calcareous rocks and stonework.

Parmelia omphalodes is a foliose lichen in the family Parmeliaceae, commonly known as smoky crottle. It forms brown, leaf-like lobes and is associated with nutrient-poor, well-lit siliceous rocks, especially on exposed outcrops and boulders at high elevations or in high latitudes. Its habitat includ...

Tephromela atra is a crustose lichen characterized by its striking white margins and black fruiting discs, formally reclassified by Austrian botanist Josef Hafellner in 1984.

Lecanora muralis, often treated under the current name Protoparmeliopsis muralis, is a placodioid lichen that forms pale yellow-green rosettes with lobed margins and disc-like apothecia. It commonly grows on exposed rock and on man-made mineral surfaces such as concrete, paving, asphalt, roof tiles,...

Dermatocarpon miniatum is an umbilicate foliose lichen that grows attached to rock by a central point. It has a leathery thallus that may appear reddish brown, with the outer portions extending away from the attachment point. The species is commonly found on calcareous rocks in the Northern Hemisphe...

Caloplaca saxicola is an orange crustose lichen that is also treated in some classifications under the genus Calogaya. Its thallus is closely attached to the substrate but becomes lobed at the margins, while orange apothecia commonly develop near the lobe tips; it lacks isidia and soredia. The liche...

Peccania coralloides is a small lichen in the genus Peccania, a group of lichens associated with cyanobacteria as their photosynthetic partner. It is recognizable by its dark, coralloid growth form, in which short branches or lobes form a compact cushion-like thallus. The species is associated with...

Physcia caesia is a foliose lichen in the family Physciaceae that usually forms small, closely attached rosettes in pale or blue-gray tones. Its upper surface may be white-spotted and bears blue-gray soralia, while black apothecia are uncommon. It is primarily saxicolous, growing on dry or periodica...

Ochrolechia parella is a crustose lichen with a thick, gray to cream thallus that may be smooth or warted and is often bordered by a white prothallus. Its pinkish to beige apothecia have swollen margins and a powdery surface, and can occur in large, crowded groups. The species commonly grows on hard...

Candelariella vitellina is a crustose lichen that forms yellow, mustard, orange, or brown-orange granules and patches. Its small apothecia are usually yellow or dull yellow and often darken with age, providing a useful feature for recognition. The species grows on siliceous and calcareous rock, conc...

Diplotomma alboatrum is a crustose lichen with a chalky white, pale gray, ochre, or pale brown thallus that is often cracked or areolate. Its small black apothecia may be covered with a whitish powder and are frequently abundant on the thallus. The species grows on calcareous and siliceous rock, bar...

Rhizocarpon distinctum is a crustose lichen that forms distinct black rings around a pale center on rocky substrates, cataloged by Norwegian botanist Theodor Fries in 1874.

Caloplaca holocarpa is a small crustose lichen in the Teloschistaceae, but the name has been used for a difficult and variable group of similar taxa. The thallus is often poorly developed or nearly absent, while the conspicuous apothecia range from yellow to orange or orange-red and are usually smal...

Gyalecta jenensis is a crustose lichen associated with shaded, basic substrates. It forms pale orange to pinkish, wheel-like apothecia that stand above the thallus and have a conspicuous thick margin, giving the fruiting bodies a clustered appearance. The species occurs on basic rock and on old mort...

Aspicilia calcarea is a crustose lichen in the family Hymeneliaceae that grows directly on hard calcareous rock. Its thallus is commonly chalky white to pale blue-grey, with a smooth or cracked-areolate surface and radial cracking toward the margins. Black or initially grey-pruinose apothecia are im...

Lecanora campestris is a pale crustose lichen that forms whitish to gray, warted or areolate colonies, often in roughly circular patches. Its apothecia are usually abundant and range from red-brown to dark brown, while soralia are absent in the commonly described form. The species grows on concrete...