Ramalina

Ramalina is a genus of lichen-forming fungi in the family Ramalinaceae. Lichens are symbiotic associations between a fungal partner and a photosynthetic partner, usually algae or cyanobacteria. In Ramalina, the thalli are typically fruticose or pendulous, with slender, flattened branches that form bushy clumps or hanging curtains on trees, shrubs, or, less commonly, rocks.

The thallus surfaces are often smooth or slightly rough, and many species produce vegetative propagules such as isidia or soredia for asexual dispersal. Sexual reproduction occurs via apothecia, which contain the fungal asci and ascospores. The chemistry of Ramalina is diverse; many species produce secondary metabolites such as usnic acid and evernic acid, among others, which can aid in identification and have ecological roles.

Ecologically, Ramalina species inhabit bark, decaying wood, or rock substrates in shaded, humid environments and are common in temperate to boreal zones. They contribute to nutrient cycling and provide microhabitats for small organisms. Like many lichens, Ramalina species are sensitive to air quality and are frequently used as bioindicators of atmospheric pollution and forest health.

Distribution is broad and cosmopolitan, with numerous species described from Europe, North America, Asia, and the Southern Hemisphere. Some species are widespread, while others are restricted to specific regions or habitats, such as montane forests or island ecosystems. Overall, Ramalina represents a diverse and ecologically important group within lichen biota.