Psoroma contortum Müll.Arg.
New Zealand material agrees closely with material from southern South America including the type (Lectotype: Cape Horn. Dr Hyades, G!).
Thallus foliose-laciniate, lobate, closely attached, 3-8(-15) cm diam. Lobes undulate, uneven or ± flat, 2-3 mm wide, short and rounded to elongate, 8-15 mm long, incised at margins, contiguous, imbricate centrally, margins entire or variously incised or notched, slightly thickened below, wavy, subascendent at apices, often ± lobulate. Upper surface bright lettuce-green when wet, pale green or grey-green on storage, thin (not as thick as in P. xanthomelanum), uneven, smooth, shining in parts, roughened, wrinkled, minutely papillate- uneven in others, epruinose, without tomentum. Cephalodia on lower surface, sparse, small, globose, becoming glomerulate, dark brownish or pale buff. Lower surface pale whitish or buff, moderately to densely tomentose, tomentum pale buff, with simple to squarrose, whitish rhizines when growing on bark, or with thick brown-black rhizines when growing on moss. Apothecia frequent, central, often crowded-contorted, 1-5 mm diam., round to irregular, disc very uneven, ± plane to convex, pale red-brown, white-pruinose, conspicuously gyrose-etched or contorted, with conspicuous concentric ridges, often centrally fissured, rarely with thalline lobules, margins shining, crenulate-striate, concolorous with thallus. Ascospores globose 14-18 µm diam.
N: South of lat. 38°S. S: Throughout, though mainly close to Main Divide, Nelson to Fiordland. A: Mainly on bark of Leptospermum, Nothofagus or Metrosideros umbellata, s.l. to 100 m.
Austral
