Cladonia stellaris is a beautiful fruticose lichen, recognized by its even clusters of branches, forming round puffs. This species is found in open woodlands and tundra, typically in drier areas. Thalli are white to pale yellow-green (containing usnic acid). Branching mainly in fours and fives, the branches with open holes at the tips. Branches obscure the central main stem. Branches are round in cross section. Thalli grow 4-10 cm tall. Other species of reindeer lichen lack the even, rounded tufts of this species.
The branches end in pycnidia, which release single-celled, asexually produced spores. Plants very rarely have apothecia. This lichen predominantly 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.