Thallus of green algal morph 1-5 (-15) cm diam., often forming extensive patches. Lobes to 10 mm diam., elongate and dichotomously branched, discrete or overlapping, apices ± truncate, bright green when wet, ± shiny, smooth, often with a median channel. Lower surface flat to somewhat ribbed, whitish to red-brown, ± darkening to black-brown towards centre, ± uniformly felted-tomentose with small, scattered, rounded, white cyphellae 300-600 µmm diam. Composite thalli of the cyanobacterial and green morphs occur together, easily distinguished when wet as contrasting bright green leaflets arising from dark blue-black, lobed thalli. Thallus of cyanobacterial morph 1-5 cm diam., often forming extensive colonies. Lobes to 20 mm diam., overlapping, margins rounded, irregularly incised, very thin and wrinkled, ± minutely dissected into small, terete or often flattened, branched isidia to 500 µm diam., often aggregated. into dense clusters, 0.2-1 mm diam., occasionally becoming densely imbricate and covering the entire surface of older parts of the thallus. Upper surface pale grey to dark grey-brown, matt, sometimes white-marbled. Lower
surface finely white-tomentose, pale brown-white, ± reticulately ridged, with white, scattered cyphellae. Anamorph: conidiomata only associated with the green algal morph; pycnidia, flat or slightly elevated, with a dark brown apex. Conidia 5-7 μm long, straight, both ends slightly swollen. Teleomorph: ascomata only associated with the green algal morph; apothecia, rarely developed; disc to 7 mm diam., red-brown. Thalline exciple paler, entire or crenulate, of small, ± rounded cells with ± uniformly thickened, hyaline walls. Epithecium red-brown, K–, conglutinated. Hypothecium dense, pale grey-brown, not clearing in K. Interascal tissue of simple paraphyses ca 3 μm diam., not swollen at the apex. Ascospores (20-)23-28(-32) × 6-7(-8) μm, 1(-3)-septate, hyaline.