Bilimbia sabuletorum (Schreb.) Arnold

    Thallus formed by warted-granules or minute squamules almost isodiametric, 0.05-0.2 mm wide, whitish or pale grey when dry, pale grey-greenish when moist. Apothecia numerous, 0.3-0.8 mm diam., disc minutely rough, flat then markedly convex and rounded and globulose when old, pinkish brown when young, later dark brown or blackish, finally matt, black when dry; exciple thin, concolourous scarcely prominent when young and soon excluded. Ascii 8-spored, 70-120 x 20-25 µm according to our measures. Ascospores fusiform, 2 to 9 septate, 18-45 x 5-8 µm according to the literature, (3)-5-7-(8)-septate and 25-40 x 5-7 µm according to our measures. Photobiont: Chlorococcales. Chemical spot tests negative. Not especially maritime, usually in our prospection area on mosses or on plant debris over calcareous dunes where it goes unnoticed if not specifically searched, sometimes on old mossy walls. N.B. Intensely pigmented forms with black apothecia have been referred to as Myxobilimbia accedens (Arnold) Hafellner; this seems to be the case here for some specimen collected on dunes. See Vezdaea aestivalis, with granular greenish thallus when moist and with apothecia not turning to black and smaller ascospores, 1-3 septate. N.B. This species is rather similar to Bacidia bagliettoana that shares the same habitat and may coexist, but apothecia of the latter are more numerous, planer, never globose and above all always black, ascospores acicular, 3-7-septate.*