Description: Primary thallus squamulose, often ephemeral but sometimes persistent and forming a bullate crust, the squamules middle-sized (1-4 mm), thick, esorediate, grey green to brown above, white beneath. Podetia robust and elongate, hollow inside, brownish grey to dark brown, becoming reddish brown to almost black at base, up to 15 cm tall and 1-4(-6) mm thick, simple or with a few branches starting from near the base, with pointed apices or with narrow, regular cups non- or sparsely squamulose toward the base, continuously corticate, smooth to often wrinked and longitudinally ridged, often somewhat glossy; transverse cracks and white medullary outgrowths often present at the base of podetia. Apothecia rare, brown, convex. 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 dark, semi-immersed, ovoid, developing along the margins of cups, with a colourless jelly. Conidia bacilliform. Photobiont chlorococcoid. Spot tests zand chemistry: two chemotypes (both C-, KC- P+ red, UV-)/: 1) K- (fumarprotocetraric acid complex and quaesitic acid). 2) K+ yellow (atranorin and fumarprotocetraric acid complex). Chemotype 1) is the most frequent.
Note: a subarctic-subalpine, circumpolar lichen, one of the most abundant species in subalpine Rhododendron heaths throughout the Alps, mostly deeply immersed amongst mosses. See also note on C. gracilis.
Growth form: Fruticose
Substrata: soil, terricolous mosses, and plant debris