Species of alga) but a few forms are known (Lecanora granatina, Solorina crocea) which make use of more than one kind in their development.
Parmelia, Lecanora), having sometimes also in addition a proper one 1 (e.g.
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.
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.
Lecanora calcarea, Lecidea calcivora and several Verrucariae), while all other saxicolous lichens may be regarded as belonging to the latter, whatever may be the mineralogical character of the substratum.
Lecanora Prevostii, Lecidea calcivora) have the power of forming minute cavities in the rock, in which they are partially buried.
Lecanora crassa, Lecidea decipiens), others sandy soil or hardened mud (e.g.
Concentrica, Lecanora esculenta); but it can hardly be that these are really free ab initio (vide Crombie in Journ.
The lichen flora of temperate regions again is essentially distinguished from the preceding by the frequency of corticolous species belonging to Lecanora, Lecidea and Graphidei.
Lecanora subfusca, Cladonia pyxidata); and others, not strictly cosmopolitan, have been observed in regions widely apart.
The highest specimen obtained was a lichen (Lecanora subfusca, L.) on the south side of Chimborazo, 18,400 ft.