in Diederich & al., Bull soc. nat. Luxemb., 113: 105, 2012. Basionym: Opegrapha culmigena Lib. - Plantae Cryptogamae quas in Arduenna coll., fasc. 1: nr. 15, 1830.
Synonyms: Opegrapha atrorimalis Nyl.; Opegrapha betulina Sm. non Pers.; Opegrapha herbarum Mont.; Opegrapha prosiliens Stirt. non Mont. & Bosch; Opegrapha protuberans Zahlbr.; Opegrapha turneri Leight.; Opegrapha varia var. herbarum (Mont.) Källsten comb. inval.
Distribution: N - Lig (Brunialti & al. 1999). C - Tosc (Senese & Critelli 2000, Loppi & al. 2004, 2004c, Loppi & Frati 2006), Umb (Ravera & al. 2011), Abr (Giordani & al. 2009). S - Pugl (Nimis & Tretiach 1999).
Description: Thallus crustose, thinly episubstratic, smooth to slightly rugose, grey-white to yellowish white, rarely delimited by a very thin, dark prothallus, sometimes poorly evident. Apothecia lirelliform, mostly simple, emergent, solitary or in small clusters, 0.3-2 x 0.1-0.3 mm. with a slit-like to slightly expanded, dark brown to black, epruinose disc, and a thick, raised, black, epruinose proper margin. Proper exciple black, carbonized, extending below the hymenium, K-; epithecium colourless to pale brown, up to 25 μm high, K- or K+ brown-red, I+ pale blue; hymenium colourless, not inspersed with oil droplets, 50-70 μm high, I+ reddish, K/I+ blue; paraphysoids branched and anastomosing, 1-1.5 μm wide, the apical cell not enlarged; subymenium colourless to very pale brown, 40-60 μm high, I+ pale blue; hypothecium black, carbonized. Asci 8-spored, elongate, cylindrical or elongate-ellipsoid, the inner layer of endoascus amyloid in upper part, with a I+ blue ring visible around a small ocular chamber, varia-type. Ascospores 3(-4)-septate, hyaline (overmature spores often brownish), subclavate with rounded ends, (16-)18-23(-26) x (3-)4-7(-8) μm, with a 0.6-1.2 μm thick, gelatinous perispore. Pycnidia black, immersed. Conidia straight, 3-7 x 0.5-1 μm. Photobiont trentepohlioid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on bark and plant debris, rarely also on wood, in areas with mild winters below the montane belt; mostly Tyrrhenian in Italy. Earlier records from Trentino (see Nimis 1993: 459) and Piemonte (Caniglia & al. 1992, Griselli & al. 2003), being dubious, are not accepted here.
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)