( in Vondrák & al.) J. Syst. Evol. 58, 3: 322, 2020.. Basionym: Caloplaca subathallina H. Magn. - Bot. Not.: 82, 1951.
Distribution: C - Abr (Di Nuzzo & al. 2021, Gheza & al. 2021, Vallese & al. 2022), Sar (Vondrák & al. 2020). S - Si (Vondrák & al. 2020).
Description: Thallus crustose, thinly episubstratic, white to grey-white. Apothecia biatorine, sessile, 0.2-0.4 mm across, with a black, epruinose disc and a thin proper margin. Proper exciple prosoplectenchymatous, brown to grey brown in outer part, colourless within, the pigmented parts K+ violet, N+ orange-red; epithecium grey-brown, K+ strongly violet, N+ orange-red; hymenium colourless, 45-75 µm high, K/I+ blue; paraphyses simple or sparingly branched in upper part, 1-1.5 µm thick at base, the apical cells up to 3 µm wide; hypothecium colourless. Asci 8-spored, clavate, functionally unitunicate, apically thickened with a broad internal beak, the inner part of apex and external cap I+ blue, Teloschistes-type. Ascospores 2-celled, polarilocular, hyaline, ellipsoid, 11-15 x 6-8 µm, the equatorial thickening (“septum”) 4-7 µm; lumina of immature spores sometimes sandglass-shaped. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC- P-. Chemistry: exciple and epithecium with unidentified anthraquinones.
Note: According to Vondrák & al. (2020), this species differs from all other species of the hungarica-group by its chemistry (chlorinated chemosyndrome only). It is known from many stations, mainly in the Mediterranean Region, and is most frequent on twigs of deciduous and coniferous trees and shrubs, with a wide altitudinal range. The only Italian stations are from Abruzzo, Sardinia and the Aeolian Islands, but the species may be more widespread in Mediterranean Italy.