Hymenelia

Hymenelia is a genus of lichenized fungi in the family Hymeneliaceae. These lichens are characterized by their crustose thallus and apothecial fruiting bodies. The apothecia are typically immersed or slightly raised above the thallus surface.

Characteristics:

• Thallus: Crustose, often inconspicuous and closely adhering to the substrate (usually rock). It can be areolate or continuous.
• Apothecia: Lecanorine (with a thalline margin) or biatorine (margin lacking thalline tissue), disc-shaped, and varying in color.
• Ascospores: Simple (non-septate), hyaline (translucent), and ellipsoid to oblong in shape.
• Photobiont: A green alga.

Habitat and Distribution:

• Hymenelia species are typically found on siliceous rocks in alpine and arctic environments, though some species occur in other habitats. Their distribution is generally widespread but may be locally restricted due to specific substrate requirements and climatic conditions.

Taxonomy:

• The genus Hymenelia has undergone taxonomic revisions, and the number of accepted species may vary depending on the source. Further research may lead to changes in classification within the Hymeneliaceae family. Distinguishing between species often relies on subtle morphological and chemical differences.

Ecological Role:

• Like other lichens, Hymenelia species contribute to weathering processes and play a role in primary succession, colonizing bare rock surfaces. They also provide a microhabitat for small invertebrates.