A lichen is neither a plant or an animal – it’s two organisms acting as one! Lichen is made up of a green algae and a fungus that live together and need each other to survive. The lichen provides the fungi with food and the fungi gives the algae water and a place to live. Lichens are often found in inhospitable places where plants struggle to grow such as on rock surfaces, on exposed mountain tops and on the tidal zone on the sea shore. Lichens are found in many different forms. Some appear like crusts on rocks, gradually spreading across the rocks surface and can even be mistaken for part of the rock. Other Lichens are much larger with branches, looking more like plants and mosses. Lichens also come in a large variety of colours and many different Lichens were traditionally used for dying Harris Tweed.
Lichens have no roots and take in their water and nutrients from the air. As a result they are very sensitive to air pollution. Many species of lichen are only found in areas with particularly clean air away from industrialised areas and some lichens are used by scientists as indicators of air pollution.
Cladonia Lichens are pale grey/green in colour, growing on rocks or thin soil amongst mosses. They are branched looking a little like red deer antlers in miniature. There are at least 3 species of Reindeer Lichen found on Harris.
Cladonia portentosa (Photo: Laurie Campbell)
Cladonia uncialis (Photo: Laurie Campbell)
Cladonia floerkeana (Photo: Laurie Campbell)
by Robin Reid