Cetraria muricata (Ach.) Eckfeldt

    Thallus in a small bush forming dense shrubs, cushion-like, 1-4 cm high, made up of strongly branched branches ending in a point and having a thorny appearance with spinules, (appearance of a miniature of a thorny bush in desert areas!) the branches have a regular and almost circular section, full of a compact medulla, shiny surface and as if varnished, rare pseudocyphellae, small, flat, circular and not located at the bottom of a depression; overall colour is very dark: blackish, blackish brown, black. Very rare apothecia. Photobiont: chlorococcoid. No significant color chemical reactions. A fairly rare species in our prospecting area, found on acidic, stony soils, scree, mine slag heaps, etc.

N.B. This taxon is very close to Cetraria aculeata whose colors are less dark, the branches more flattened, hollow with an irregular section and whose pseudocyphellae are larger, oval and at the bottom of a depression.

N.B. This species is even so close to Cetraria aculeata that some authors consider it to be a simple variety or even a simple form (ecoform), and with all intermediate specimen between the two forms. Cetraria muricata grows in much more exposed environments and simply might be a fom of  Cetraria aculeata  subjected to harsh conditions. Additional investigations are required in order to clarify this issue.