( in Vondrák & al.) J. Syst. Evol. 58, 3: 322, 2020.. Basionym: Caloplaca subathallina H. Magn. - Bot. Not.: 82, 1951.
Distribution: C - Abr (Gheza & al. 2021), Sar (Vondrák & al. 2020). S - Si (Vondrák & al. 2020).
Description: Thallus crustose, episubstratic, grey, continuous to areolate, <100 μm thick, sometimes delimited by a black prothallus. Apothecia biatorine, dark red (rarely orange-red), sessile, 0.3-0.5 mm across, with a flat to slightly convex disc and a smooth, often paler, thin proper margin (thalline margin always absent). Proper exciple prosoplectechymatous, orange in outer part, colourless within, amyloid; epithecium orange-brown, granular, K+ red, C+ purple in section; hymenium colourless, not inspersed with oil droplets, amyloid; paraphyses sparingly branched, 1.5-2 μm thick in lower part, the uppermost cells only slightly swollen; hypothecium colourless to pale yellowish brown. Asci 8-spored, cylindrical-clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, ellipsoid, (12-) 13-14(-15) x (4-)5-6(-8) μm, the septum 4-6 µm thick. Pycnidia rare, dark grey, with Cinereorufa-green. Conidia bacilliform, rarely narrowly ellipsoid, 3-5 x 1-1.5 μm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-; apothecia K+ red C+ purple in section. Chemistry: chlorinated anthraquinones in apothecia, plus non-chlorinated anthraquinones with parietin reduced or absent; thallus without anthraquinones; Cinereorufa-green hardly detectable, except in pycnidial walls.
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.