Psilolechia
Crustose lichens containing Stichococcus or sometimes with trebouxioid algae; thallus crustose, leprose or, rarely, areolate, bright yellow-green, dull green, bluish green, or pale grey; apothecia rimless, adnate; hymenium formed of somewhat gnarled, once- or twice- branched paraphyses (not anastomosing) embedded in gel, not densely pigmented in any part; hypothecium colourless; asci clavate, with a thick tholus that reacts IKI+ light blue with a darker blue tube (appearing as two upwardly diverging, more or less straight lines extending up the entire height of the tholus); spores 8 per ascus, colourless, simple, oblong-ovate or narrowly ovate.
References: Purvis et al. 1992.
Psilolechia lucida (Ach.) Choisy
Thallus sorediate and more or less leprose, or sometimes a bit dense and stratified, sometimes with a cottony white hypothallus, light to bright yellow-green, containing rhizocarpic acid (UV+ orange); photobiont trebouxioid, or less often Stichococcus; apothecia rare, 0.1-0.3 mm wide, matte, orangish tan, rimless, high-convex; spores narrowly ovate, 4-7 × 1-2 µ.
Reactions: UV+ yellow-orange
Contents: Rhizocarpic acid.
Habitat: Usually on rock, but also found on bark or wood, always close to the ground and usually where sheltered from rain splash, lower to middle elevation (rarely upper elevation) forests.
Similar Species: Sterile thalli of Chaenotheca brachypoda and C. furfuracea are very similar, but are UV- or + weakly yellow-orange and always contain Stichococcus. Also similar in appearance is Chrysothrix chlorina, which is UV-.
Specimens: Björk 17835.
Local Status: Uncommon as an epiphyte.