Synonyms: Biatora meiocarpa (Nyl.) Arnold; Lecidea meiocarpa Nyl.; Lecidea minuta auct. non (Nyl.) Nyl.
Distribution: N - TAA (Nascimbene & al. 2022), Lomb, Lig.
Description: Thallus crustose, rimose-areolate or small-areolate, sometimes partly endosubstratic, pale beige to greyish green. Apothecia biatorine, rounded to rarely deformed-tuberculate, sessile and constricted at base, 0.45-0.6 mm across, with an orange brown to brown, epruinose, flat to slightly convex disc, and a thin, usually paler, sometimes indistinct, finally excluded proper margin. Proper exciple colourless throughout to orange-brown in innermost part, laterally 30-75 µm wide, of radiating hyphae with 1.5-3.5 µm thick lumina, the apical cells 2-6 µm wide; epithecium scarcely differentiated from the hymenium, colourless or rarely with with orange-brown droplets; hymenium colourless to pale golden brown, 40-55 µm high; paraphyses simple or weakly branched and anastomosing, 0.7-1.2 µm thick at mid-level, the apical cells 1.5-4 µm wide; hypothecium colourless. Asci 8-spored, clavate, with a K/I+ blue apical dome penetrated by a narrow, K/I- apical cushion surrounded by a narrow, deeply K/I+ blue zone, the wall K/I- but surrounded by an I+ red-brown, K/I+ blue outer layer, the ocular chamber relatively small, Biatora-type. Ascospores 1-celled (rarely a few 1-septate), hyaline, (8-)10-15(-23) x 3-4(-5) µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: Ekman (1994) states that this is is a northern species, confined to Fennoscandia; reports from central Europe could be due to misidentifications, perhaps with the similar B. helvola, with Lecania cyrtellina, or with epiphytic samples of B. subduplex. All Italian records (see Nimis 1993: 386) should be checked.