|Wolf Moss Lichen & fabrics: top: Silk Chiffon Bottom: Silk Charmeuse|
Habitat: Letharia vulpina is most commonly found in dry coniferous forests. The species also occurs in Europe southward to North Africa. The species is found on twigs and stumps of most conifers. In Washington, you won't find it in coastal Douglas-fir rain forests, but in drier inland Douglas-fir stands, where it can be very abundant. It seems to be adapted to summer dryness [in fact, the alga's photosynthetic maximum is 7oC, and doesn't drop much even to 0oC, (the freezing point)]. So it is active mostly during winter precipitation. There are, however, instances of the lichen found on bark of other trees, and human made substrates like houses and fence posts. It sometimes occurs on rocks.
Use: Used as a yellow dye. For this purpose it was boiled in water, alone or with Oregon grape bark. This dye was used mainly for basket materials and fibers. As a medicine, this lichen was boiled and taken in a weak solution for internal problems and, in stronger solution, was used to wash external sores and wounds.
This lichen is... poisonous that the Achomawi in Northern California used it to make poison arrowheads.
And how did the common name come about? It deals with the European usage, which (barbarians that they were) was destructive. It was mixed with ground glass and meat and used to kill wolves. The vulpinic acid is toxic, although it is not clear if the ground glass may have been enough to do the job. Perhaps it caused stomach perforations and allowed the vulpinic acid (note the name) to be readily absorbed.
Another excellent description of this fascinating plant can be found on Wikipedia.