A rim lichen, crabseye lichen (Ochrolechia tartarea, syn. Lecanora tartarea), from which the powder is obtained.
A violet-red powder, difficult to moisten with water, prepared from certain lichens, especially Ochrolechia tartarea (syn. Lecanora tartarea), and used for making violet or purple dye.
Any of several lichens, especially those of the genera Roccella and Lecanora.
The dye, orcein, extracted from them.