Biatora globulosa

Thallus effuse, pale white-fawn, thin, smooth to powdery, ± rimose or endoxylic; photobiont cells 7–14 (–18) μm diam., absent in the thalline margin. Apothecia sessile, numerous, 0.15–0.4 mm diam., at first flat, soon convex to subglobose, usually grey-brown or grey- to green-black, rarely pale in shade morphs, occasionally white-pruinose when young; proper margin indistinct from above, colourless except the upper edge which is often concolorous with the epithecium, the hyphae coherent in K, lumina ellipsoidal, 2–4 μm diam.; epithecium mostly slate-grey to dark olive-green, K+ green intensifying, N+ red; hymenium 30–40 μm tall, colourless; hypothecium colourless; paraphyses 1.2–2 μm diam., unbranched or forked above; the apical one or two cells often grey- or green-walled and swollen to ca 6 μm diam. Ascospores 7–12 (–16) × 2–2.5 μm, 0- to 1-septate, cylindrical to cylindric-fusiform. Pycnidia inconspicuous, partly immersed, 40–100 μm diam., black; the wall dark green; conidiogenous cells in a single layer, short-ampulliform; conidia of two types (a) cylindrical or ± curved, 3.5–5 (–6) × 0.5–0.7 μm (commoner), or (b) ellipsoidal, 2–2.8 × 1–1.5 μm; the two types not in the same pycnidium.

The usually black discs and apothecia lacking photobiont cells distinguish this species from Lecania chlorotiza and L. cyrtellina. It is often difficult to distinguish in the field from Biatora beckhausii, with which it often grows.