Opera Bot., 127: 116, 1996. Basionym: Bacidia rubella var. assulata Körb. - Parerga Lichenol.: 131, 1860.
Synonyms: Bacidia anomala A. Massal.; Bacidia assulata (Körb.) Vězda; Bacidia effusa auct.; Bacidia intermedia (Hepp ex Stizenb.) Arnold nom. illegit. non (Hampe) A. Massal.
Distribution: N - TAA (Nascimbene & al. 2007b), Lomb. C - Tosc, Sar (Zedda 2002). S - Camp (CLU 17515), Pugl (Jatta 1909-1911), Bas (Jatta 1909-1911), Cal (Jatta 1909-1911), Si.
Description: Thallus crustose, episubstratic, continuous to granulose, whitish or greenish grey, partially dissolved into loosely aggregated, 16-29 μm wide goniocysts in small patches. Apothecia biatorine, 0.3-0.6 mm across, pink, brown-orange or purple-brown, often mottled, with a flat, epruinose disc and a concolorous, distinct proper margin. Proper exciple laterally c. 60 μm wide, without crystals, of rather thin-walled (2-3 μm), radiating hyphae, orange-brown in the outher rim, colourless within; epithecium orange-brown, scarcely differentiated from the hymenium; hymenium colourless in lower part, orange-brown in upper part, 60-75 μm high; paraphyses c. 1.2 μm thick at mid-level, the apical cells 2.5-3.5 μm wide, without internal pigment; hypothecium colourless or very pale yellow; all pigmented parts of apothecia K+ intensifying, N-. Asci 8-spored, cylindrical-clavate, approaching the Bacidia-type, the ocular chamber wide, the axial body never penetrating through the entire d-layer, surrounded by a narrow, darker amyloid layer. Ascospores 5-9-septate, needle-like, straight or curved, 34-45(-54) x 1.5-2.5 μm. Pycnidia immersed, colourless. Conidia 1-celled, filiform, curved, 10-43 x (0.5-)0.8-1 μm. Photobiont chlorococcoid, the cells 5-12 μm in diam. Spot tests: thallus and apothecia K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances; apothecia with the Rubella-orange pigment.
Note: according to Ekman (1996) Italian material of this epiphytic lichen does not belong to this species, and still awaits a formal description. The species is included in the Italian red list of epiphytic lichens as “Data Deficient” (Nascimbene & al. 2013c).