On walls and rocks (synanthropic); somtimes corticolous; very common.

Thallus large (up to 10 cm diam.), forming regular rosettes (looking like a spat out chewing gum), becoming uneven when old; marginal squamules flat to concave; with many apothecia in the center.
Cortex K-, C-, KC+ yellowish, Pd+ yellowish (or -).

Central Europe; Germany: Hesse.