Species of alga) but a few forms are known (Lecanora granatina, Solorina crocea) which make use of more than one kind in their development.
Lecanora metaboloides, Lecidea decolorans), while sometimes they are white or glaucous, rarely greenish, pruinose.
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.