Thallus pale yellowish green, dominated by deeply dissected squamules resembling richly branched coralloid isidia, 18–30 μm diam. and to 300 μm tall, corticate, with a shiny surface when dry; photobiont cells 5–12 μm diam.
Anamorph: Pycnidia rare, immersed in the thallus to sessile.
Teleomorph: apothecia 0.3–0.8 mm diam., usually absent, at first barrel-shaped but soon becoming flat, white or with a pink-orange disc and whitish margin; true exciple colourless, with cellular lumina 4–7 (–9.5) μm diam. and to 12 μm long; hymenium 50–55 μm high, colourless; epithecium colourless, K–; hypothecium colourless; paraphyses 1.2–1.7 μm diam., unbranched or a few forked near the apices, apices 2.7–4 μm diam. Ascospores 47–71 × 1.5–1.7 μm, narrowly 3- to 5-septate, acicular.
Description from LGBI3. Map © British Lichen Society
W. Britain and Ireland; frequent.
On bark, often over bryophytes, of a wide range of deciduous trees and shrubs in humid, oceanic woodlands.