Cladonia rangiferina is a much-branched fruticose lichen found in open woodlands and dry alpine tundra. Thalli grow 4-12 cm tall. The thallus is greyish, often with a pale brown or pinkish cast, richly and evenly branched. The branches are round in cross section, becoming finer with brownish tips. Notably, and unlike other reindeer lichens, the branches all are bent in one direction, appearing swept to the side. The dying base is brownish. Cladonia stygia is also grey and has a similar habit (branches bent in one direction), but the base of the thallus is blackened.
The branches end in pycnidia, which are specialized structures that release single-celled, asexually produced spores. Plants very rarely have apothecia. This lichen also reproduces by fragmentation.
The reindeer lichens are highly important forage for caribou in the winter. They contain many chemicals which are low-level toxins; caribou are specially adapted to excrete these compounds. In times of starvation, Native peoples would collect reindeer lichen, boiling them many times to remove toxins and then eating them.