Fuscidea cyathoides forme altérée.
Thallus crustose, thick, markedly uneven with closed warts, swellings, cracks and fissures, pale greyish, pale brown-greyish, prothallus dark-brown, especially visible in case of mosaics. Apothecia numerous, immersed at first, then slightly protruding, seldom regular but often distorted, sometimes forming small muriform-like mounds, discs rough, powdery, brown, dark-brown, blackish, exciple wavy, paler, vanishing when mature. Ascii 8-spored, 55-75 x 10-15 µm. Ascospores ovoid, ellipsoid to broadly ellipsoid, becoming kidney-shaped when mature, simple or 1-septate, 10-13 (15) x (4) 5-6 (7) µm according to our measures. Photobiont: chlorococcoid. Thallus: C-, K-, Pd+ golden yellow to orange; medulla: C- (or faint yellow if the sodium hypochloride solution contains soda), K+ yellow, KC+ yellow, Pd+ yellow > orange. This taxon is found on siliceous rocks subjected to sea-spray. Its unusual aspect in the field suggests a Miriquidica colony but ascospore analysis under microscope reveals a majority of kidney-shaped ascospores and consequently suggests a taxon close to Fuscidea cyathoides.
N.B. Appears to be an extreme and old form of Fuscidea cyathoides forme maritime.