Parmelia (fungus)

Parmelia is a genus of foliose (leafy) lichen-forming fungi in the family Parmeliaceae. Characterized by their relatively large size and broad, lobed thalli, Parmelia lichens are widely distributed and can be found on a variety of substrates including rocks, trees, and soil.

The distinguishing features of Parmelia include a gray to greenish-gray upper surface, a black lower surface with rhizines (root-like structures) for attachment, and the presence of pseudocyphellae (small pores on the upper surface). These pseudocyphellae aid in gas exchange. The apothecia (fruiting bodies) are typically disc-shaped and located on the upper surface of the thallus.

Parmelia species reproduce both sexually through ascospores released from the apothecia, and asexually through fragmentation and the production of soredia (small clusters of algal cells and fungal hyphae).

The taxonomy of Parmelia has undergone significant revisions, and many species formerly classified within Parmelia have been reclassified into other genera within the Parmeliaceae. This reclassification has been based on morphological, chemical, and molecular data. As a result, the current definition of Parmelia encompasses a more restricted group of species than historically recognized.

Parmelia lichens play an important ecological role as primary producers and contribute to nutrient cycling in various ecosystems. They are also sensitive to air pollution and can be used as bioindicators of environmental quality.