Its branches tend to be coarser, more copiously branched from the base, and more strongly curved in one direction. The 2 species cannot be separated with certainty in the field, but they are easily identified using chemical tests. The Woods Cree boiled green reindeer lichen to make a medicinal tea for expelling intestinal worms. The powdered lichen was also taken in water for this purpose. Reindeer lichens provide important ground cover in northern woodlands.
Lichens are the principal winter food of many caribou, reindeer and musk-oxen.
Although hoofed mammals can survive for several months on a lichen diet, they usually lose body weight because of protein deficiency. The complex carbohydrates of the lichens are broken down by enzymes produced in the stomach of reindeer or caribou but in few other animals. The bacteria and protozoans in the rumen also help to break down lichen compounds into sugars that the animals can use. Humans cannot digest lichens and get little energy from eating these plants. However, partially digested lichen from the stomaches of freshly killed caribou was often eaten, and in this form it has much greater nutritional value.