Thallus orbicular to spreading, in patches to 5(-10) cm diam. Upper surface minutely granular-uneven ± arachnoid or "frosted" often minutely verruculose, occasionally areolate-cracked, whitish to pale greenish-grey or glaucous-grey. Apothecia sparse to frequent, 0.1-0.5 mm diam., solitary, or scattered, to 4-5 together in a line, often in a declivity in bark or 2-4(-7) together in a pseudostroma, round to irregular, innate, disc concave to plane, red or red-brown, rarely black, translucent, densely covered with a thick, white granular pruina, margins white or pale pinkish, slightly raised, entire to dentate-irregular, ± puckered, split or fissured or ± gyalectiform, or eroded to a ± translucent, thin, red rim. Ascopores fusiform, slightly curved (5-)7-13-septate, (45-)54-90(-100) × 5-10 µm. Chemistry: Cortex K+ yellow → red. Norstictic acid.