Distribution: N - Frl, Ven (Nascimbene & Caniglia 2003c), TAA, Lomb, Piem (E.C.I. 568: Roux & Triebel 1994, Isocrono & al. 2003), VA (Piervittori & Isocrono 1999). C - Abr (Gheza & al. 2021), Sar (TSB 21722).
Description: Thallus squamulose, heteromerous, rather thick, olive-yellowish to ochraceous brown both when dry and when moist, with pale punctiform depressions in a reticulate pattern. Squamules subpeltate, 1.5-2(-3) mm broad, at first flat, then concave, contiguous, with rounded ends and a down-turned edges, attached by a mat of 10-14 µm thick, colourless rhizohyphae. Upper cortex paraplectenchymatous, (12-)25-50(-70) µm thick, of periclinally arranged hyphae, covered with a 7-12 µm thick epinecral layer; medulla poorly developed; lower cortex absent or restricted to the margins. Apothecia without a thalline margin, semi-immersed in the squamules, up to 2 mm diam, with a dark reddish brown, concave to flat disc, and a thin to indistinct proper margin. Proper exciple 20-50 µm wide laterally; epithecium brownish, K-; hymenium colourless, 120-180(-195) µm high, K/I+ reddish; paraphyses mostly simple, lax, distinctly thickened above; hypothecium colourless, 20-35 µm high. Asci 8-spored, cylindrical to obovoid, prototunicate, thin-walled, K/I-. Ascospores 1-celled (sometimes apparently 1-septate), hyaline, ellipsoid, thin-walled, 20-23 x 7-8 µm. Pycnidia dark, immersed. Conidia fusiform, 2.5-3.5 x 1-1.5 µm. Photobiont cyanobacterial (Scytonema-like). Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a cool-temperate to boreal-montane, circumpolar, ephemeral lichen of disturbed calciferous soil in dry, open grasslands; in the past it was frequently confused with the Mediterranean-Atlantic H. lutosa. An earlier record of this species from Sicily has been assigned to toH. lutosa.
Growth form: Squamulose
Substrata: soil, terricolous mosses, and plant debris