Micarea micrococca (Körb.) Gams ex Coppins

    Thallus minutely granular, sometimes slightly leprose, composed of several layers of numerous globose goniocysts, 12-15 µm diam., sometimes aggregated in larger granules, to 25-50 µm diam., suggesting somewhat a Lepraria aspect, if thick, more or less cracked , gelatinous towards margins when moist, green, grey-green when moist, bright green tinged yellow when dry. Apothecia usually numerous, convex to subglobose, possibly tuberculate, 0.1-0.4 mm diam., white-pink at first, then grey-brown and finally blackish, immarginate except sometimes when young. Ascospores broadly ellipsoid, 1-septate, 8-12 x 3-4 µm. Pycnidia white or greyish around ostioles. Photobiont: micareoid. Chemical spot tests negative (or seldom C+ yellow-orange).  Not especially maritime, but may be found on stumps, wood debris on the ground, decaying timber, seldom in fissures of acid rocks, in shaded and humid areas. N.B. This is the most common species of the Micarea prasina s.l. group from which its differs by its chemical composition just as Micarea subviridescens that would have more maritime trends and found in rock crevices near the seashore. Micarea micrococca and Micarea subviridescens are sometimes considered as Micarea prasina s.l. chemotypes. In fact the problem is more complex and according to the latest molecular phylogeny data, Micarea micrococca encompasses 3 different taxa. The specimen presented here have been partially analysed and the chemical spot tests suggest that they belong to Micarea micrococca but this has still to be confirmed. Not to be confused with some forms of Lecania erysibe of which the apothecia are not globose and the photobiont different and not a micaroid (unicellular cells with binary fission).*