Verrucaria lapidicola  

Thallus diffuse, very thin, 25–35 µm thick, dull grey-green to dull grey-brown, smooth, often minutely and inconspicuously mottled, not gelatinous, not areolate or cracked. In section comprising distinct or indistinct goniocyst-like units 18–33 µm diam., mostly in a single layer, composed of angular cells 3–9 x 3–6 µm in size. Prothallus not detected. Photobiont cells 7–12 x 5–8 µm in size.
Anamorph: not known.
Teleomorph: ascomata perithecia, 160–280 µm diam., projecting, black, exposed or occasionally with an incomplete thalline covering over the  lower two-thirds, the apex rounded or slightly flattened, ostiolar region whitish to pale brown, plane or protruding as a low papilla, 30–40(–60) µm diam. Involucrellum conical-hemispherical, densely pigmented throughout or hyaline at base next to the ascoma wall, not becoming confluent. Ascomatal wall colourless at sides and base. Interascal tissue absent, but with periphysoids ca 12 µm long. Asci 85–90 x 23–24 µm, 8-spored. Ascospores (17–)18–21.5(–23) x 6.5–8 (–10.5) µm, (2.2–) 2.5–2.8(–2.9) times as long as wide, ellipsoidal, colourless, aseptate.