It is often of a pale chestnut color, but varies considerably, being sometimes almost entirely grayish-white; and grows to a height of from 7.6 to 10.2 centimetres (3 to 4 inches), the branches being channeled into flattened lobes with fringed edges.

[2] It grows abundantly in the mountainous regions of northern countries, and it is specially characteristic of the lava slopes and plains of the west and north of Iceland.

[3] Cetraria islandica is a known host to the lichenicolous fungus species Lichenopeltella cetrariicola, which is known from Europe and Iceland.

[7] It forms a nutritious and easily digested amylaceous food, being used in place of starch in some preparations of hot chocolate.

[2] It is traditionally used to relieve chest ailments,[8][better source needed] irritation of the oral and pharyngeal mucous membranes and to suppress dry cough.