When you come to Jokkmokk you will see them everywhere: lichen. A lichen is a symbiotic organism between algae or cyanobacteria and fungi. They are extremely powerful organism, which live in extreme environments and get very old, up to some thousand years! Lichens come in many colours, sizes, and forms.
Lichen are an important part of the reindeer diet during winter. Probably, you have seen the so-called reindeer-lichen in other context for decoration purposes!
The winter lichen (Arctoparmelia centrifuga) is a layer that grows on rocks. The circular shape is because the lichen grows outwards while older inner parts die. That is the reason why the winter lichen is sometimes playfully called the ”Russian Empire”. In hard winters with a lot of snow, reindeer will graze on this type of lichen also.
On some stone blocks and concrete walls you can sometimes see a thin red coating. It consists of Trentepohlia, which is not a lichen but an algae that specializes in a life in the air. The species is the most common in the tropics, but three species occur in Sweden. If you scratch a stone with violstensalg (Trentepohlia iolitus) when it’s moist, a strong smell like violett.