Synonyms: Blastenia viperae Zahlbr.; Caloplaca viperae (Zahlbr.) H. Olivier
Distribution: N - VG (TSB 11262), Emil (Arup & Åkelius 2009, Vondrák & al. 2020, Fariselli & al. 2020). C - Tosc (Arup & Åkelius 2009), Laz, Sar (Vondrák & al. 2020). S - Pugl (TSB 2230), Cal (Vondrák & al. 2020), Si (Herb. Malícek 7591).
Description: Thallus crustose, episubstratic, continuous to cracked-areolate, more or less densely covered with (50-)56-90(-112) μm tall, beige to orange, rarely grey or green, coralloid isidia. Apothecia biatorine/zeorine, adnate to sessile, round to very irregular in outline, orange to rust-red, with a concave to convex disc, and a thin proper margin. Proper exciple 60-85 μm thick, prosoplectenchymatous, of more or less radiating, elongate cells, sometimes containing algae in lower part; epithecium orange, granular, K+ red; hymenium colourless, 80-105 μm high, not inspersed with oil droplets; paraphyses simple or sparingly branched in upper part, 1-2.5 μm thick, the apical cells sometimes slightly wider; hypothecium colourless or very pale brown, 50-110 μm high, often inspersed with oil droplets. Asci 8-spored, clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, ellipsoid, 10-15 x 4-9 μm, the septum (3-)3.5-4(-5) μm thick. Pycnidia rare, immersed, with a red ostiole. Conidia bacilliform to narrowly ellipsoid, 3-5 x 0.8-2 μm. Photobiont chlorococcoid. Spot tests: orange parts of thallus and apothecia K+ red; margin of apothecia and tips of pycnidia C+ purple. Chemistry: non-chlorinated anthraquinones in apothecial disc, chlorinated anthraquinones in exciple and tips of pycnidia; thallus without or with anthraquinones; Cinereorufa-green only in traces (in prothallus and tips of blastidia).
Note: A recently-described, Mediterranean-Macaronesian and Mediterranean-Atlantic species reaching S Scandinavia, but absent from most of Central Europe, more frequent at lower altitudes than B. herbidella. It might be that several samples of B. herbidella found in lowland areas of Central-Southern Italy could belong to this taxon.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)