Scythioria

Scythioria is a small genus of lichen-forming fungi in the family Teloschistaceae. It comprises three species. Species in this genus are found primarily in the Palaearctic realm, occurring in Eurasia and North Africa. They typically grow on the bark of broad-leaved trees in forested areas, as well as on plant debris, soil, and small shrubs in steppe and semi-desert environments. They are occasionally found on rock surfaces. The body (thallus) of species in this genus forms a crust-like (crustose) growth that either appears as small islands (areolate) or becomes embedded within tree bark or rock surfaces. The colour ranges from greenish-white to bright yellow. Scythioria species typically produce abundant powdery reproductive structures called soredia, and have a thin outer layer (cortex) made up of rounded cells that is often not well-developed....read more on Wikipedia.