It is bright yellow-green, shrubby and highly branched, and grows on the bark of living and dead conifers in parts of western and continental Europe and the Pacific Northwest and northern Rocky Mountains of North America.

This species is somewhat toxic to mammals due to the yellow pigment vulpinic acid, and has been used historically as a poison for wolves and foxes.

In one set of experiments, the lichen was able to reactivate its metabolism after 15 hours of cold storage and resume photosynthesis within 12 minutes of thawing.

[6] The use of this species for poisoning wolves and foxes goes back at least hundreds of years, based on the mention of the practice in Christoph Gedner's "Of the use of curiosity", collected in Benjamin Stillingfleet, Miscellaneous Tracts Relating to Natural History, Husbandry and Physics (London, 1759).

[7] The toxic chemical is the yellow dye vulpinic acid, which is poisonous to all meat-eaters, but not to mice and rabbits.