Verrucaria pallidomurina  

Thallus at least partly epilithic, dirty white to grey-brown, thalli often discoloured by superficial cyanobacteria, very thin, to 80 μm thick, often discontinuous, cracks none to numerous, often only in thicker pockets or around perithecia; in some specimens also partly endolithic amongst rock crystals; thallus not composed of goniocyst-like units.
Anamorph: not known.
Teleomorph: Perithecia forming low and often ill-defined to well-developed mounds 180–300 (–360) μm diam., black, without a thalline covering; ostiolar area inconspicuous or rarely visible as a pale dot or minute papilla. Involucrellum well-developed, spreading outwards and downwards, reaching 0.3–0.8 of the way down exciple, 55–75 μm thick; brown, K+ greenish brown. Exciple 160–235 μm diam., colourless or brown. Periphyses ca. 13-30 μm long in situ. Ascospores (19.5–) 21.5–25.5 (–28.5) × 11–12.5 (–13.5) μm, perispore not detected.

Description adapted from Orange (2020).