Thallus thin, 25–60 µm thick, smooth, continuous or sparsely cracked, grey-green to mid-brown, ± translucent when fresh and wet. Cells irregularly arranged, at most with a very weak vertical arrangement, coherent, with no air spaces between them. Cortical pigment, when present, brown. Adjacent conspecific thalli never separated by dark lines.
Anamorph: not known.
Teleomorph: ascomata perithecia, forming conical-hemispherical mounds 240–400 µm diam., at first covered to the apex by a layer of thallus, later with the black apex of the involucrellum sometimes exposed. Ostiolar area inconspicuous, plane or convex, appearing as a pale dot 15–50 µm diam. Involucrellum conical, extending below to the substratum, densely pigmented on the upper part, often becoming almost hyaline adjacent to the base of exciple; pigment dark brown to dark reddish brown, K+ darker brown to grey-brown. Ascomata 145–225 µm diam., colourless except at the apex. Interascal tissue absent, but periphyses and periphysoides present. Asci clavate, I–, fissitunicate, the wall thickened above, ocular chamber usually present; dehiscence by extrusion of an endotunica to form a delicate rostrum, 8-spored. Ascospores arranged biseriately, (15–) 19.5–23 (–26) x (6.5–)8–9.5 (–11) µm, (1.7–) 2.2–2.6 (–3.3) times as long as wide, ellipsoidal, hyaline, aseptate, thin-walled, perispore not seen.
Assessed (as Verrucaria hydrela) by Woods & Coppins (2012) as of Least Concern. The species appears to be widespread and common in suitable habitats.
Distinguished by the smooth, thin thallus, small perithecia, the conical involucrellum which is covered by a thin layer of thallus, and rather small ascospores (fide Orange 2013).
Verrucaria placida and V. andesiatica (sensu Orange et al. 2009) differ in the larger and more widely spaced perithecia and the larger ascospores (Table 2). V. dolosa differs in the distinctly smaller ascospores (15–18 x 6–8 µm), smaller, more crowded perithecia, and lack of a regular thalline covering to the mature perithecium (Orange 2013).
Throughout the British Isles, mostly in the north and west. BLS map: see here.
On rocks and stones in streams, streamlets, and seepages.