Chrysothrix

Chrysothrix is a genus of lichen-forming fungi in the family Chrysotrichaceae. They are commonly called gold dust lichens or sulfur dust lichens, because they are bright yellow to greenish-yellow, sometimes flecked with orange, and composed entirely of powdery soredia. Apothecia are never present in North American specimens. They grow on bark or rocks, generally in shaded habitats. They can sometimes be mistaken for sterile specimens of Chaenotheca, which usually has pinhead apothecia on tiny stalks, or Psilolechia, which usually has small, bright yellow apothecia. Chrysothrix chlorina was traditionally used as a brown dye for wool in Scandinavia. ...read more on Wikipedia.