Rinodina gennarii Bagl.

    Thallus crustose, thin and sometimes evanescent, more or less smooth to rimose and slightly verrucose, pale grey, dark grey, olive-grey, grey-brownish. Apothecia lecanorine, usually numerous, sometimes clustered, sessile when mature, 0.2-0.8 mm diam., disc flat but soon becoming convex, brown-black, blackish, exciple usually thin, persistent, paler. Ascii club-shaped, 8-spored, 50-55 x 20-25 according to our measures. Ascospores brown, broadly ellipsoid, 1-septate, widened at septa level (distinct in 5% K solution), 13-16 x 7-9 µm according to the literature, 11-17 x 7-10 µm according to our measures. Photobiont: Trebouxia. Chemical spot tests negative. Grows on nutrient-rich calcareous or basic silicated rocks, but in our prospection area, grows also on stone walls, concrete, bricks, seldom on rotten wood and artificial substrates (plastics).

N.B. Very variable species (or collective?) both by the variations of its thallus and by the size of its spores but also by its habitat! Pending studies to clarify the problem we use the name Rinodina oleae for the very similar wood taxon, but with yellowish tones, occurring on the wood of wooden boat wrecks, poles or street furniture in particular by the sea.

N.B. Often together with Myriolecis (Lecanora) dispersa.