Distribution: N - VA (Matteucci & al. 2015d), Emil (Benesperi 2009, Fariselli & al. 2020). C - Tosc (Craighero 2010), Marc (Nimis & Tretiach 1999), Abr (Nimis & Tretiach 1999), Sar (Craighero 2010). S - Cal (TSB 4686), Si (Nimis & al. 1996b, Ottonello & Romano 1997).
Description: Thallus crustose, episubstratic, continuous to fissured, whitish, pale grey or greenish grey, often weakly zoned at margin, delimited by a white prothallus, tasting extremely bitter. Central parts of thallus with numerous, circular, 0.5-2 mm wide, white, strongly convex to hemispherical soralia. Apothecia not known. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-; soralia and medulla K-, C- KC+ fleeting violet, P- or P+ reddish, UV-. Chemistry: picrolichenic acid, sometimes with additional protocetraric and conprotocetraric acids.
Note: on siliceous rocks. A very critical taxon, which badly needs revision, perhaps just a saxicolous form of L. amara.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)