Cladoniaceae

Cladoniaceae is a family of lichen-forming fungi in the order Lecanorales, within the class Lecanoromycetes of the Ascomycota. The family includes several genera, with Cladonia being the best known and most speciose. Other genera traditionally placed in the group include Stereocaulon, and in some taxonomic treatments Cladina is treated as part of Cladonia.

Description of members typically portrays fruticose lichens with erect, branching podetia arising from a crustose or squamulose base. The tips of many podetia bear cup-like structures or apothecia. The forms vary widely, and many species are commonly referred to as cup lichens or reindeer lichens.

Distribution and habitat span worldwide, but Cladoniaceae are especially common in temperate and boreal regions. They occupy a range of substrates, including soil, moss, rotting wood, and rock, often in nutrient-poor environments. Reindeer lichens, comprising several Cladonia species such as Cladonia rangiferina and relatives, form important forage for caribou and reindeer in northern ecosystems.

Ecology and reproduction: the fungal partner forms a symbiosis with a photosynthetic green alga, typically Trebouxia or related genera. Reproduction occurs sexually via apothecia and asexual propagation through structures such as soredia or isidia in many species. Cladoniaceae contribute to soil formation and nutrient cycling and can be prominent components of tundra and boreal communities.

Chemistry and significance: members produce a variety of lichen secondary metabolites with ecological and chemotaxonomic relevance; these compounds are of interest in studies of lichen biology and biodiversity. The group is also used in bioindicator research for air quality and ecosystem change.

Notes: Taxonomy within Cladoniaceae is dynamic and shaped by molecular data, leading to reclassification of certain genera and species in recent decades.