Description: Thallus very variable, from squamulose-peltate to subfruticose, mono- or polyphyllous, 350-550 µm thick, gelatinous when wet, black when dry, olive-brown when wet, forming up to 1-1.5 cm wide and 0.5-0.6 mm tall cushions attached by bundles of rhizohyphae or by a central holdfast; lobules erect, 2-6 mm tall, 0.3-0.5 mm wide, cylindrical or slightly flattened, simple or sparingly branched, smooth or granulose. Outer part of squamules (in section) 60-80 µm wide, formed by 2-3.5 µm thick, mainly anticlinally oriented hyphae enclosing the photobiont cells, the medullary part of loosely arranged, 1-2 µm thick hyphae with cylindrical cells, the basal part forming a denser strand of irregularly arranged hyphae. Apothecia thallinocarps, sunken in thallus and difficult to recognize unless when wet, terminal, 0.3-0.8 mm across, with a convex, fissured disc, without a distinct margin. Proper exciple indistinct; epithecium brownish, discontinuous, 12-20 µm high; hymenium 75-110 µm high, separated into partial compartments by wedges of photobiont cells from the epithecium, covered by a irregularly thick layer of sterile tissue and a layer of photobiont cells, I+ blue turning wine-red; subhymenium continuous, 20-49 µm high. Asci 16-32-spored, with a thin, one-layered, non-amyloid wall, an amyloid external apical cap, and passive spore discharge via apical rupturing. Ascospores 1-celled, hyaline, broadly ellipsoid to subglobose, 4-9 x 3-5 µm. Photobiont cyanobacterial, chroococcoid, with clusters of 2-6 cells measuring 5-10 x 3-6 µm penetrated by haustoria and surrounded by a brownish gelatinous sheath. Spot test: all negative. Chemistry: without lichen substances.
Note: a species described from the Middle East and also known from NE Africa, the SE part of the Iberian Peninsula, and the Sonoran Desert, growing on steeply inclined surfaces or more or less calciferous or basic siliceous rocks, often on thin layers of sand in rock fissures, in dry, sunny sites with periodical water seepage after rain. To be looked for in the driest parts of Mediterranean Italy.