Thallus
Crustose, more or less adherent to the substrate, formed of granules of variable size (0.05–2 mm), giving some species a powdery appearance. The determination to the species level requires a microscopic observation to measure the granule size.
Color
Mustard yellow, greenish-yellow or yellow-orange
Reproduction
Apothecia: present in some species, about 1 mm in diameter, disc darker in color than margin (3)
Soralia: present in some species, like very small granules (0.05 mm)
Isidia: —
Substrate
On bark, rock, or artificial substrate
Habitat
Slightly nitrophilous
Sensitivity to air pollution
Resistant to pollution