Buellia abstracta (Nyl.) Olivier

    Thallus more or less visible, immersed, rimose-cracked, whitish. Apothecia immersed or sessile, 0,2-0,5 mm diam., aligned or clustered, disc black, flat to slightly convex, pruinose, thin margin more or less distinct. Ascospores 1-septate, constricted at septum level, 11-13,5 x 4,5-5,5 µm; 11-14 x 4.5-5.5 µm according to our measurements. Photobiont : Chlorococcales. Thallus: C-, K+ yellow > red, Pd+ red-orange (N.B. sometimes chemical spot tests are negative or slow). On small standing stones (menhirs) and large exposed pebbles on the seashore. N.B. On the field, aspect of Sarcogyne but species of this genus have negative chemical reactions and simple ascospores.*