Miriquidica deusta (Stenh.) Hertel & Rambold

    Thallus crustose, tightly appressed to the substratum, areolate, areoles squamulose, 0.5-1.5 mm, more or less scattered on a conspicuous black prothallus, surface smooth and bright, edges irregular more or less crenulate and upturned, dark brown, brown-blackish, blackish, margin greyish, prothallus large, blackish to black, limits indistincly defined. Not fertile in our prospection area, elsewhere apothecia immersed in the thallus at first, then slightly prominent, 0.5-0.8 mm diam., disc  plane, black and not powdery, exciple thin and crisped, greyish, suggesting  a black mat covered with flowers or ice crystals. Ascospores ellipsoid, simple, colourless, 10-12 x 4-5.5 µm. Photobiont: Trebouxia. C-, K-, CK-, Pd-, I-. Rare, on large granite rocks on well-lit summits.

N.B.1. Highly variable (described under different names and even genera), its frequency might be underestimated since at first it suggests a common Verrucaria...

See also Lecidea fuscoatra of which the prothallus is not black and as developed, paler brown and usually fertile with apothecia slightly convex and powdery.

N.B. 2 This species seems to come close to Rhizocarpons sp. yellow (see: Miriquidica deusta et Rhizocarpon viridiatrum) such as Miriquidica intrudens which is a parasite of these Rhizocarpons sp. yellow, but also in the vicinity of Lecidea fuscoatra of which it could also be a parasite, at least in its youth.