Rinodina aspersa (Borrer) J.R. Laudon subsp. atrocinerea (Hook.) Cl. Roux

    Thallus crustose, thin, sometimes fragmented towards margins and then showing a black prothallus, areolate, areoles more or less crowded, with round edges, dull whitish, grey-bluish, pale grey-brownish, pale brownish, prothallus usually well developed, black. Apothecia lecanorine, usually numerous, 0.5-1 mm diam., immersed at first in the thallus, then slightly prominent, disc flat then slightly convex, dark brown, thalline exciple distinct, pale brownish or concolourous to the thallus. Ascospores broadly ellipsoid belonging to the Pachysporaria type ; pale brown-greenish or slate coloured when immature, brownish when mature, 15-21 x 7-13 µm according to literature, 15-18 x 9-14 µm according to our measurements. Photobiont : trebouxioid. Cortex : C+ red-orange, K+ yellow, Pd+ yellow. Oceanic and maritime affinities, common near the seashore, growing on vertical walls of siliceous rocks or large stones. Very similar to Rinodina aspersa subsp. aspersa but not sorediate. N.B. Numerous intermediate taxa seem to occur between the two sub-species, notably near the seashore, see Rinodina aspersa s.l.  littoral intermediate form and also Rinodina atrocinerea that has been kept at species rank until additional research clarify this issue.*