Psoroma contextum Stirt.
Lectotype: New Zealand. Near Wellington. J. Buchanan 46/74, 1874, BM!
Thallus squamulose, very closely attached, spreading, 4-6(-10) cm diam., prothallus only rarely present, black, thin, somewhat eroded, scattered. Squamules small, 1-3 mm diam., flattened, lobate-crenate, distinctly placodioid at margins, pressed together, separated by fine black cracks like a jigsaw puzzle, rarely imbricate at margins, becoming minutely lobulate and subimbricate centrally in a close mosaic, surface smooth, waxy, shining, margins not pubescent- frosted, dark green to pale green or whitish or yellowish-grey not darkening on storage. Cephalodia rare, simple, globose to ± glomerulate, not flattened- placodioid, pale brown-grey, surface smooth, not wrinkled or striate-cracked, developed below squamules, protruding from margins of squamules, to 0.8 mm diam. Apothecia sessile to subpedicellate, scattered to crowded, projecting above squamules, round to subirregular, to 2 mm diam., margins concolorous with thallus, waxy, crenate-striate, obscuring disc in young fruits, disc red- brown, matt, often darkening centrally, rarely with a single to a few thalline lobules centrally, plane or subconcave, not etched-contorted, fissured or pruinose. Ascospores ellipsoid to fusiform 18-24 × 12-17 µm.
N: S: St: A: Throughout, south of lat. 38°S, mainly west of the Main Divide in South I., mainly in Nothofagus forest on bark and among moss on tree trunks in damp, semi-shaded habitats.
Austral
