Thallus pale grey, very thin, continuous or lacking, sometimes minutely cracked, sorediate, prothallus black, or lacking. Soralia numerous, seldom confluent, often forming a mosaic to 2 mm diam., soredia farinose, less than 0.01 mm diam., greenish-grey in freshly gathered material, pale yellowish-grey on storage, ± delimited in circular, plane or subconvex soralia. Apothecia rare (not seen in New Zealand material) sessile, plane at first with a prominent proper margin, becoming convex and immarginate. Epithecium dark brown. Hymenium colourless 110-120 µm tall. Hypothecium dark brown. Asci clavate, 110 × 15 µm. Ascospores pseudomuriform, ellipsoid (13-)15-28 × 7-13 µm.