Gray reindeer lichen
The gray reindeer lichen is a species of lichen that is typical to the boreal forest, growing to a height of between 5 to 10 centimetres (2 to 4 in.). It is found in abundance to the north of the 50th parallel. This lichen grows in open, dry terrain which is often sandy. It grows slowly, and some clusters of lichen may be a hundred years old.
The survival of the woodland caribou, Rangifer tarandus caribou, in winter is closely linked to the presence of the gray reindeer lichen. The caribou removes the snow with its hooves in order to reach the lichen which grows flush with the ground.