Flora of New Zealand Series

Thallus closely to loosely attached, orbicular to spreading 3-15 cm diam., saxicolous, or corticolous. Lobes sublinear-elongate, subdichotomously branched, rather narrow (to 10 mm wide), margins entire, sinuous. Upper surface pale greenish-grey to blackish-grey often with a distinctly bluish tinge, shining, not maculate, occasionally white-pruinose, wrinkled-faveolate, pseudocyphellae prominent, coarse, elongate and reticulate, soon becoming sorediate. Soredia derived from pseudocyphellae, in lines as a coarse reticulum, or becoming confluent. Lower surface black with little or no naked marginal zone, densely rhizinate. Rhizines black, simple to squarrosely branched. Apothecia and pycnidia not seen in New Zealand material. Chemistry: Cortex K+ yellow; medulla K+ yellow → red, C-, KC+ red, Pd+ orange. Salazinic acid and atranorin.

S: Nelson southwards. St: A: Inland and coastal, from s.l. to 2000 m. Mainly saxicolous, rarely on soil or bark.

Cosmopolitan

P. sulcata is similar to P. saxatilis, and in New Zealand the two species occupy similar habitats with P. signifera, but it is distinguished from these species by the presence of soredia associated with the pseudocyphellae reticulum. P. erumpens is separated from P. sulcata by the erumpent, subcoralloid soredia which are not associated with pseudocyphellae or arranged in any reticulate pattern.