Kryptog.-Fl. Deutschl. 2: 37 (1845).

Basionym: Verrucaria polytropa Ehrh. in Hoffm., Deutschl. Fl.: 196 (1796).

Type: Germany, Harz, "In Hercyniae", Ehrhardt: Plantae Cryptog. Linneae: 294 (LINN-Smith - isotype).

Thallus: cryptothalline, up to 40 mm in diameter. Apothecia irregularly roundish to angular, crowded, ca. 40 per square centimeter, constricted at the base, ca. 0.6 - 0.8 - 1.5 mm in diameter, disc subconvex to convex, pale brownith, matt, epruinose. Margin at first obvious, later more or less vanishing, pale whitish, matt. Excipulum 70 - 100 µm, lateral of hymenium 60 - 80 µm thick. Ectal zone colourless, hyphae ca. 6 µm in diameter, with lumina of 2 - 3 µm. Inner zone colourless, incrusted with lichen substances, hyphae 3 - 4 µm in diameter, with lumina of ca. 1.2 - 1.5 µm. Medullary zone at the basal part of the excipulum, with algal cells. Hypothecium colourless, hyphae ca. 3 µm in diameter, subhymenial layer colourless. Hymenium 50 - 55 µm tall, colourless, I + blue, epihymenium pale brown, 10 - 15 - 18 µm high, paraphyses occasionally branched, not anastomosing, ca. 1.7 - 2 µm, apices 3 µm thick, asci 30 - 40 - 45 / 10 - 12 - 14 µm, tholus 2.5 - 5 - 10 µm, amyloid zone above masse axiale not obvious, outer amyloid wall layer ca. 0.2 µm thick, I + or -, spores ellipsoid, 9 - 10 - 12 / 5 - 5.5 - 6 µm. Pycnidia unknown (Rambold 1989: 104 two lecideoid specimens).

Photobiont: Data lacking.

Chemistry: Cortex K + yellow, P -, C -, medulla K -, P -, C -, excipulum K -, P -, C -. Usnic acid, zeorin (trace), rangiformic acid (trace) (Rambold 1989: 104 two lecideoid specimens).

Ecology: Silicious stone.

Molecular data: Genbank

Distribution: Database

Note: "According to Hertel (1971), P. W. James has ensured the identity of this isotype with the modern concept of the species" (Rambold 1989: 104).