Sarcogyne hypophaea (Nyl.) Arnold
Sarcogyne privigna H. Magn. (auct. non (Ach.)) A. Massal.
Polysporina simplex (Taylor) Vezda p.p.
Sarcogyne privigna (Ach.) A. Massal ?
Thallus more or less endolithic, gelatinous when moist and otherwise evanescent and hardly visible, pale greyish. Apothecia sessile, 0.5-1 mm diam., disc flat to convex, very dark brown-red, brown-blackish, blackish, not pruinose, exciple black, not crenulate, sometimes irregular owing compression with neighbouring apothecia. Asci containing a high number of spores (over 100). Ascospores simple, minute, 3-5 x 1-1,5 µm. Photobiont: Myrmercia. Chemical spot tests negative. This species is not especially maritime, but grows in crevices and cracks of large-grain siliceous rocks (mainly of walls and concrete blocks of piers and jetties). Not to be confused with Sarcogyne clavus maritime of which apothecia are larger and usually more reddish and exciple crenulate and with Sarcogyne regularis that grows on calcareous rocks and of which the powdery apothecia have a thin exciple soon excluded. On mortar, avoid confusion with Clauzadea monticola of which the apothecia are more globose and asci 8-spored. Polysporina simplex is sometimes considered as synonymous but differs by its apothecia with rugose or pleated discs.
N.B. The interpretations as to the name to be used for this species vary considerably according to the authors see: K. KNUDSEN, J. KOCOURKOVA, M. WESTBERG. The identity of Sarcogyne hypophaea (Nyl.) Arnold. Opuscula Philolichenum, 12: 23-26. 2013.