Thus ascogonia with trichogynes have been observed in Endocarpon, Collema, Pertusaria, Lecanora, Gyrophora, Parmelia, Ramalina, Physcia, Anaptychia and Cladonia.
They are characterized by their insolubility or very slight solubility in water; as examples may be mentioned erythrinic acid in Roccella and Lecanora; evernic acid in species of Evernia, Ramalina and Cladonia; lecanoric acid in Lecanora, Gyrophora.
Of considerable value is the " perelle " prepared from Lecanora parella, and used in the preparation of a red or crimson dye.
Inferior to this is " cudbear," derived from Lecanora tartarea, which was formerly very extensively employed by the peasantry of north Europe for giving a scarlet or purple colour to woollen cloths.
This is derived chiefly from Lecanora esculents, which grows unattached on the ground in layers from 3 to 6 in.