Distribution: N - Ven (B-60 0195311), TAA (Nascimbene & al. 2022), Lomb, Piem (Isocrono & al. 2004), VA (Piervittori & Isocrono 1999).
Description: Thallus crustose, episubstratic, thin to well-developed, continuous or minutely areolate, grey to dark greenish grey, sometimes partly immersed and forming small dark patches. Perithecia black, forming hemispherical projections, 0.6-0.8(-1) mm across, with a rough surface, rarely with a very thin thalline collar at the base, the ostiolar region usually depressed. Involucrellum more or less fused with exciple, or somewhat diverging in lower part, thicker around the ostiole. exciple 15-25 μm thick, brown, paler in lower part; hamathecium of periphyses and periphysoids, interascal filaments absent; periphysoids numerous, slender, 1.5-2.5 μm wide; hymenial gel hemiamyloid, I+ red (+ blue at very low concentrations of I), K/I+ blue. Asci 8-spored, broadly ellipsoid to clavate, K/I-, fissitunicate, wall thickened above when young. Ascospores muriform, dark brown when mature, the cells outlines mostly obscured, ellipsoid to broadly ellipsoid, 63-85 x 35–50 μm. Photobiont chlorococcoid, but verrucose cephalodia with Nostoc frequent. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: in the central European mountains A. alpina grows on calcareous rocks (mesozoic limestone, marble of variable age) with at least locally increased humidity; it is widely distributed in the Alps and not at all rare: probably a considerable percentage of the records of Henrica theleodes, especially those upon pure limestone, refer to this species.