THALLUS: light to greenish gray, continuous to fissured, often white spotted near margin
SOREDIA: covering apothecia and sometimes coalescing in center of thallus
APOTHECIA: generally infertile, covered with white coarsely granular soredia
CHEMISTRY: soredia KC+ violet (picrolichenic acid), cortex PD- or PD+ red (with or without protocetraric acid)
Northern hemisphere.
Common Name: Bitter Wart Lichen
Grayish crust lichen with piles of granular-sorediate bitter-tasting infertile apothecia.
Bark of mostly deciduous but occasionally coniferous trees, rarely siliceous rocks. In shady places.