Distribution: N - Lomb (Rivellini & Valcuvia 1996), Piem (Morisi & Sereno 1995, Isocrono & al. 2006), Lig (Ravera & al. 2016, Gheza & al. 2020). C - Tosc (Brackel 2015). S - Cal (Puntillo 1996).
Description: Primary thallus squamulose, the squamules very small, 1-3(-4) mm long, 0.9-2 mm wide, crenulate-incised, often contorted, densely sorediate especially along the margins and on the lower surface, sometimes dissolving into greenish to brownish masses of soredia, yellowish green above, white beneath. Podetia rare, yellowish grey in upper part, often orange yellow at the base, usually simple to very sparsely branched in upper part,often deformed, more or less flattened or club-like, 1-4(-7) mm tall, 0.3-1(-2) mm thick (but luxuriant specimens may be up to 3 cm tall and much branched in upper part), with a partly corticate, partly granulose-verruculose, sometimes partly farinose-sorediate surface, rarely squamulose. Apothecia rather rare, scarlet red, at the tips of podetia, often confluent and to 2.5 mm across. Asci 8-spored, clavate, thickened at apex, with a K/I+ blue tholus and a K/I+ strongly blue outer gelatinous sheath, Cladonia-type. Ascospores 1-celled, hyaline, ellipsoid. Pycnidia scarlet red, semi-immersed in the primary squamules, with a red jelly. Conidia cylindrical. Photobiont chlorococcoid. Spot tests: K-, C-, KC- or KC+ yellow, P-, UV+ white. Chemistry: usnic, squamatic and didymic acids; some rare strains contain also grayanic acid; rhodocladonic acid in apothecia and pycnidia.
Note: a cool-temperate to boreal-montane species with a fragmented circumpolar range, found on peaty and humus-rich soil and on strongly weathered lignum.
Growth form: Fruticose
Substrata: soil, terricolous mosses, and plant debris
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)