Squamules: up to 2.5 mm diam., rounded to elongated, partly ascending, irregularly imbricate. Upper side: pale olivaceous brown, dull to slightly shiny, epruinose, smooth or with a few shallow fissures; margin: white, finely pruinose, straight or only slightly upturned, entire; underside: white to pale brown. Upper cortex: @. Medulla: @. Lower cortex: @. Apothecia: up to 1 mm diam., attached laminally to the squamules, simple, immarginate and strongly convex to hemispherical even when young, reddish brown, dull, faintly orange pruinose. Ascospores: @ x @ μm. Pycnoconidia: not seen. Thallus chemistry:atranorin.
The small, pale olivaceous brown, white-edged squamules containing atranorin and the reddish brown, laminal apothecia are diagnostic. Psora rubiformis and P. testacea are both larger species; the former has brownish black to black apothecia and contains usnic acid and gyrophoric acid, the latter has more orange apothecia which are attached marginally to the squamules.
The species is known from a few collections from Japan.
The species is saxicolous, but very little additional information is available. In one collection (Kashiwadani, Lich. Minus Cogniti Exsicc. 338), the collection site is described as "rock along stream" at 110 m alt.
Psora rubiformis, Psora testacea
