(1) the main chemotype contains salazinic acid (K+ red, Pd+ yellow to orange) with different accessory substances (protocetraric, barbatic, caperatic acids) (Halonen et al. 1998); (2) chemotype with psoromic acid (K–, Pd+ yellow) is the rarest (Halonen et al. 1999); (3) chemotype without medullary compounds (K–, Pd–) is known both in Europe and North America.
In Estonia chemotypes (1) and (3) are reported (n=12 and n=5, respectively) (Tõrra & Randlane 2007).

Distinction from closely related taxa see under U. diplotypus.

Europe (map legend)
Corticolous. Reported in Europe: Austria, Bulgaria, Czech Republic, Estonia, Finland, Germany, Italy, Latvia, Lithuania, Norway, Poland, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine.

Estonia
Grows mainly on conifers (on Picea 37% of examined specimens, on Pinus 24%, on other 22%), on Betula (15%) and on lignum (7%). Very frequent in Estonia (53 specimens), found mainly on the northern coast and in south-eastern region of Estonia (Tõrra & Randlane 2007).