Rinodina roboris var. armeriicola Matzer & Sattler

    Thallus usually thick, more or less nodulous or cracked, slightly papillate, very pale greyish, white-glaucous, pale grey-greenish, grey-green, grey-blue, green-bluish tinge clearly visible even from afar, prothallus absent or inconspicuous. Apothecia more or less contiguous, 1-1,5 mm diam., disc flat, dark brown becoming blackish, thalline exciple irregular to crenulate, concolourous to the thallus.  Ascospores 1-septate, broadly ellipsoid, 14-22 x 8-12 µm. Photobiont: Trebouxia. C-, K+ yellow, KC-. Typically near the seashore, on the ground amongst or on the roots of Armeria maritima (photo n° 3) or Calluna sp.. Maritime species, rare, also found in Scilly Islands and in Cape Lizard and Galicia. Close to Rinodina beccariana but  typically grows on bare soils amongst or on roots of armerias and heathers.