Ascolichens

Ascolichens refers to the assemblage of lichens that are predominantly found in the Ascoli Piceno region of the Marche region in central Italy. The term is informal and is used by field lichenologists to describe a set of species that share similar ecological adaptations within this Mediterranean climate zone. Ascolichens are typically crustose or foliose in growth form and colonise calcareous stone, bark of oaks and beech trees, and occasionally anthropogenic substrates such as local stone walls. The region’s moderate humidity and moderate winter temperatures favor a diverse lichen flora but are particularly favourable for genera such as Parmelia, Xanthoria, Evernia and Cladonia, which frequently occur in Ascoli.

Morphologically, collec­tions identified as ascolichens tend to exhibit pale spotted thalli, which are often indicative of exposure to high levels of airborne nitrogen. A common reproductive structure among ascolichens is the pigmented apothecium, which is frequently round or ellipsoid and displays a dark margin. Many ascolichens produce cyanobacteria as secondary symbionts, especially in the genus Rhizocarpon. In the most studied seasons, the local lichen community lists over 30 species, including some rare taxa such as Sticta breakdowni and a locally endemic species, Cladonia ascoliensis, which is only reported from the stone walls of the Castello di Ascoli.

Historically, the name ‘ascolichens’ first appeared in local naturalist literature in the early 20th century and has since been used in field guides to represent a recognizable element of the regional biodiversity. Ascolichens are considered valuable bioindicators of air quality and habitat stability, providing early warning signals for industrial pollution levels and climatic shifts in the Marche area. Their conservation is typically addressed through protection of stone‐wall habitats and monitoring of emissions from nearby urban centres.