Synonyms: Marfloraea excludens (Nyl.) S. Y. Kondr., L. Lőkös & J.-S. Hur; Pertusaria excludens Nyl.; Pertusaria inopinata Erichsen?
Distribution: N - Frl (Tretiach & Hafellner 2000), VA (Isocrono & al. 2008, Matteucci & al. 2015d), Lig. C - Tosc, Sar (Nöske 2000, Craighero 2010, Rizzi & al. 2011). S - Si (Craighero 2010).
Description: Thallus crustose, episubstratic, rather thick, markedly cracked and areolate, whitish grey, matt, sorediate, often delimited by a thin, pale prothallus. Areoles flat to slightly convex, irregular in outline, more or less angulose, (0.2-)0.5-1(-2) mm wide, finely granulose or papillate. Soralia abundant, white, 0.5-1(-1.5) mm across, convex to excavate, slightly paler than the areoles, discrete to finally confluent, bursting from the thalline warts and finally covering almost the whole thallus surface; soredia coarsely granular. Apothecia extremely rare, often aborting, hidden beneath the soredia. Ascospores unknown. Photobiont chlorococcoid. Spot tests: soralia K+ yellow turning blood red (needle-like crystals), C-, KC+ yellow-red, P+ yellow-orange, UV+ pale grey or grey-yellow. Chemistry: norstictic acid (major), salazinic acid (minor or traces), plus a UV+ yellow xanthone.
Note: on steeply inclined surfaces of sheltered siliceous rocks, probably more widespread also in the Alps.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)