Synonyms: Callopisma rubellianum (Ach.) A. Massal.
Distribution: N - Ven, TAA (Hafellner 2015), Lomb, Piem (Isocrono & al. 2004), VA (Piervittori & Isocrono 1999), Emil (Fariselli & al. 2020), Lig. C - Laz, Sar. S - Camp, Si (Ottonello & Puntillo 1995, Vezda Lich. Rar. Exs. 164!).
Description: Thallus crustose, episubstratic, areolate, well-delimited, sometimes with a grey prothallus, pinkish grey to cinnamom-red, forming patches to 2 cm in diam. Areoles flat, smooth, up to 1.5 mm wide, the peripheral ones usually larger than the central ones. Cortex cellular, 10-30 µm thick; medulla poorly developed, dense. Apothecia frequent, immersed in the areoles, 0.2-0.5 mm across, with a scarlet red, at first often concave, then flat, epruinose disc and a persistent, but thin and poorly evident margin. Exciple of elongate to oval cells, prosoplectenchymatous below the hypothecium; epithecium orange, granular, K+ red; hymenium colourless, 55-75 µm tall; paraphyses sparingly branched in upper part, c. 2 µm thick at base, swollen at apex; hypothecium colourless. Asci 8-spored, broadly clavate, Teloschistes-type. Ascospores 1-septate, polarilocular, hyaline, ellipsoid, (7-)8-11 x 4-7 µm, the septum 3-5 µm thick. Photobiont chlorococcoid. Spot tests: thallus and apothecia K+ red, C-, KC-, P-. Chemistry: thallus and apothecia with parietin (major), fallacinal, emodin, teloschistin and parietinic acid (minor), corresponding with chemosyndrome A of Søchting (1997).
Note: a warm-temperate to subtropical, widespread lichen found on steeply inclined surfaces of hard, basic siliceous rocks (especially basalt), often with species of Peltula. The species could belong into Brownliella Y. Kondr. (Arup in litt.).
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
On otherwise dry surfaces with short periods of water seepage after rain