Distribution: N - Ven (Nascimbene & Marini 2010), Lomb (Sundin & Tehler 1998, Ravera & al. 2023), Piem, Lig (Jatta 1909-1911). C - Tosc, Laz, Abr. S - Camp (Puntillo & al. 2000), Cal (Puntillo 1996, Puntillo & Puntillo 2004, 2012).
Description: Thallus crustose, endosubstratic or thinly episubstratic, sometimes evanescent, dirty orange, ochraceous or whitish, sometimes delimited by an orange-violet prothallus. Apothecia arthonioid, very variable in shape, from ellipsoid to weakly lirelliform, often confluent into stellate groups, 0.2-0.6 x 0.1-0.2 mm, with a reddish brown to brown-black, sometimes thinly white-pruinose disc, the marginal areas with a crimson-red pruina. Proper exciple poorly developed, brown, 7–20 μm wide; epithecium yellowish brown, 10-20 μm high, K+ purple; hymenium colourless to yellowish red, 40-50 μm high, K-, J+ blue; paraphysoids 1-2 μm thick, conglutinated only in lower parts, the branched tips 3(-4) μm wide, free, extending horizontally above the asci; hypothecium poorly developed, 10-25 µm high, colourless to pale yellowish brown. Asci 8-spored, broadly clavate to subglobose, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, Arthonia-type, without K/I+ blue tholus structures. Ascospores (1-)3-4(-5)-septate, hyaline turning pale brown-when overmature, oblong-ovoid, with a larger cell at one apex, (15-)17-20(-22) x (6-)7-9(-10) μm. Photobiont trentepohlioid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: thallus without lichen substances; anthraquinones in epithecium.
Note: a mild-temperate lichen found on smooth bark, e.g. of Corylus, in humid woodlands, such as along rivers, often with Pseudoschismatomma rufescens. The Italian material needs revision: some Italian records may prove to belong to Coniocarpon cuspidans (Nyl.) Moen, Frisch & Grube (see e.g. Cannon & al. 2020). The species is included in the Italian red list of epiphytic lichens as “Vulnerable” (Nascimbene & al. 2013c).
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)