Distribution: N - TAA (Brackel 2016), Lomb (Brackel 2013, 2016), Piem (Brackel 2016). C - Tosc (Brackel 2016), Pugl (Brackel2016).
Description: Thallus inapparent, not lichenized, the hyphae developing inside the hymenia of Lecanora-species, especially of the L. polytropa-group. Apothecia arthonioid, black, 0.12-0.15 mm across, with a slightly convex disc covered with a hyaline gelatinous sheet, and without a proper margin. Proper exciple poorly developed, not evident; epithecium grey-brown, K-; hymenium colourless, I+ deep wine-red, K/I+ blue; paraphysoids septate, branched, c. 2 μm thick, apically swollen and pigmented; hypothecium reddish brown, K+ pale olive brown. Asci (4-)8-spored, broadly clavate to subglobose, semi-fissitunicate, with a large, non-amyloid apical dome, and a distinct ocular chamber, Arthonia-type. Ascospores 1-septate, hyaline, ellipsoid to slightly soleiform, 8.5-12 x 4-5 μm, indistinctly halonate. Photobiont absent. Spot tests: K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: a rarely recorded parasite in the hymenia of Lecanora species, especially of the L. polytropa-group. It was also reported from Toscana and Trentino-Alto Adige (as Arthonia clemens on Protoparmeliopsis muralis, Nimis & al. 1990, BSM 2006-2012), but these finds should be reinvestigated, as the hosts (Protoparmeliopsis muralis, L. varia) leave some doubts about the identity.