Lecidea auriculata agg. Th. Fr.
Lecidea diducens Nyl.
Lecidea sarcogynoides Körb.
Species belonging to this group share common properties: thallus restricted to a few areoles, flat, greyish, intertwined with a grey fibrillose hypothallus, evanescent or even absent. Apothecia isolated or in small clusters in granite crevices, 0.5-1.8 mm diam., sessile, disc flat to concave, bright, black, exciple thin, black, persistent, thicker, flexuose, crenulate when old, sometimes seemingly restricted to fragments in case of apothecia compression. Ascospores simple, ellipsoid to cylindrical, 7-11 x 2-3 µm. Photobiont: Trebouxia. Thallus: chemical spot tests negative. On granitic rocks, exposed southward.
Both following species are coastal:
Lecidea diducens Nyl.: thallus rimose, apothecia exciple cup-shaped; C+ carmine. On granitic rocks or large pebbles.
Lecidea sarcogynoides Körb. : thallus more or less absent. Apothecia smaller, 0.5-1.5 mm diam., markedly constricted towards the base, hymenium red-purple, exciple purple-black with a greyish external ring. Ascospores narrowly ellipsoid, apices rounded, 10-12 x 2,5-3,5 µm. Thallus, C-, K-, KC-, Pd- (common to this group). Margin section: K+ violet. Thermophile, on sunny and southward granitic rocks in the Morgat to Sainte Anne de la Palud area.*