Teloschistes chrysophthalmus

Teloschistes chrysophthalmus, sometimes referred to as the gold-eye lichen or golden-eye, is a fruticose lichen with branching. Their sexual structures, apothecia, are bright-orange with spiny projections situated around the rim.

Taxonomy
In 1768, German botanist Johann Gerhard König, a pupil of Carl Linnaeus, visited Cape Town on his way to India and made several collections of lichen species. Among these was the type collection of Lichen chrysophtalmos, now known as Teloschistes chrysophthalmos, which was first formally described by Linnaeus in 1771. Theodor Magnus Fries transferred the taxon to the genus Teloschistes in 1861, and it has been largely known by this name for more than 150 years.

In 2013, Sergey Kondratyuk and colleagues proposed to resurrect Niorma, a genus originally proposed by Abramo Bartolommeo Massalongo in 1861. The new version of the genus is to contain the species complex centred around Teloschistes hypoglaucus, a group that includes T. chrysophthalmos. However, the use of the genus has not been universally accepted by contemporary lichenologists. In a 2021 research paper, Wilk and colleagues suggest that "Teloschistes forms a genetically diverse but strongly supported clade", and they prefer to use the older classification proposed by Arup et al. in 2013 until more data are available.

Habitat and distribution
The lichen has a cosmopolitan distribution, and is most common in dry, sun-exposed areas with a temperate climate, in both the Northern and Southern Hemispheres. It is often localized and rare in many parts of its range. Colonies most often form along coastal areas.

It is a twig species, meaning that it grows on twigs. It is rarely abundant. Several sites were discovered along the coast of England during 2012 and 2013, where the hosts include hawthorn and apple trees. In America it is known to grow on California live oak, dwarf coyote brush, Peritoma arborea, and magnolias.

This species has been studied for anti-viral secondary metabolites and was found to contain parietin which exhibits virucidal effects against certain arenaviruses (Arenaviridae).