Cetrelia cetrarioides W. L. Culb. & C. F. Culb.

Cetrelia cetrarioides (Duby) W. L. Culb. & C. F. Culb. Description. Thallus foliose, heteromerous, dorsiventral, loosely attached, forming wavy, wide-spreading, usually orbicular, wide patches. Upper surface greenish-grey, lower surface black in the central part to brown at the lobe edges. Lobes broad and rounded, up to 20 mm wide, with raised margins. Pseudocyphellae on upper surface punctiform, small to rather large, usually not raised, often lacking in the central parts of thallus; pseudocyphellae on lower surface frequently present, at least on some ascending, contorted lobe apices. Soralia primarily marginal, elongated, usually very smooth and strongly convex, with fine soredia (25–35 µm). Lower surface wrinkled, with scattered, simple, black rhizines and a rhizine-free zone along the margin. Apothecia lecanorine, with brown disc. Found fertile only once in Italy (Piemonte: Val Anzasca). Chemistry. Cortex with atranorin (sometimes in low concentrations); medulla with perlatolic acid (major), imbricaric acid (minor or absent), anziaic acid (traces or absent). Distribution in Italy. All of the Alps (108 specimens from 40 sites), but more frequent in the central-eastern part: Friuli Venezia Giulia (23 specimens from 11 sites), Veneto (25 specimens from 7 sites), Trentino Alto Adige (27 specimens from 14 sites), Lombardia (28 specimens from 6 sites), Piemonte (5 specimens from 2 sites). Fig. 2. Habitat. Beech, gray alder, coniferous or mixed beech-coniferous forests in the montane belt (400–1450 m a. s. l.). Phorophytes. Abies alba, Acer pseudoplatanus, Corylus avellana, Fagus sylvati ca, Fraxinus excelsior, Larix decidua, Picea abies, Quercus pubescens, Salix appendiculata, Salix caprea, Salix sp., Ulmus sp. Literature. Confirmed citations: Veneto: Obermayer and Mayrhofer (2007), Nascimbene et al. (2010); Trentino Alto Adige: Obermayer and Mayrhofer (2007), Lang et al. (2010), Nascimbene (2014), Nascimbene and Marini (2015), Trindade et al. (2021), Nascimbene et al. (2022); Lombardia: Gheza (2019), Ravera et al. (2021). Erroneous citations (specimens belonging to other species): Emilia Romagna: Tretiach et al. (2008) (C. olivetorum), Fariselli et al. (2020) (C. olivetorum). Specimens examined. See Suppl. material 1.