(1) chemotype with protocetraric and fumarprotocetraric acids as main compounds (K± brownish, Pd+ red) and several substances as accessories is known in Europe and North America; (2) chemotype with salazinic and norstictic acids as main substances (K+ red, Pd+ yellow to orange) and with different accessory compounds has been reported from Fennoscandia (Halonen et al. 1999); (3) acid deficient chemotype without medullary substances (K–, Pd–) has also been mentioned (Clerc 1987b, Myllys 1994, Brodo et al. 2001).
In Estonia chemotype (1) is common (n=7) (Tõrra & Randlane 2007).

Easily recognized by morphological characters (small shrubby thallus, constriction of secondary branches at their base, presence of rather large soralia, and absence of both papillae and isidiomorphs). Medullary chemistry is of great help in case of chemotype (1) as fumarprotocetraric and protocetraric acids do not occur as main compounds in other shrubby species.

Europe (map legend)
Corticolous. Reported in Europe: Austria, Belgium, Bulgaria, Czech Republic (probably extinct), Denmark, Estonia, Finland, Germany, Great Britain, Hungary, Italy, Lithuania, Norway, Poland, Portugal, Romania, Russia, Slovakia (probably extinct), Slovenia, Spain, Sweden, Switzerland, Ukraine.

Estonia
78% of examined specimens grow on Picea, and 11% both on Pinus and on Betula; other substrates are not known for this Usnea in Estonia (Tõrra & Randlane 2007) while Alnus is the prevailing phorophyte in Finland and Russian part of East Fennoscandia (Myllys 1994). Rather frequent (13 specimens), reported mainly in paludified forests in southern and south-eastern regions of Estonia; still, latest collection dates back to 1959. Not recorded in Latvia, and in Lithuania only one verified locality is known (Motiejūnaitė 2002).