Two chemotypes are known from the study area (but the material from Belgium: Ard. has not yet been studied by TLC):

chemotype I (± atranorin, fumarprotocetraric, ± angardianic and ± rangiformic acids):

Over siliceous and sandstone rocks, often growing over mosses in well-lit and exposed conditions, exceptionally corticolous, on Fagus.

Belgium: Ard.: ?.

Luxembourg: Lorr.: RR.

France: Mosan: RRR, Ard.: RRR.

chemotype II (atranorin, stictic acid complex, rangiformic and ± norrangiformic acids):

Over siliceous rocks, often growing over mosses in well-lit and exposed conditions.

Belgium: Ard.: ?.

Luxembourg: Ard.: RR.

France: - .

Lit.: NL84: 15, NL92: 171, Kukwa & Diederich (2007).