Hareshaw Linn : Facts About Lichens

Ever wondered what the strange grey/green growths are that appear on the rocks and trees in Hareshaw Linn?  

They are lichens (pronounced like-ens or litchens).  Lichens are in fact two organisms living together as one. They are a unique relationship between a fungus and an algae.  Different types of lichen occur when different combinations of fungi and algae grow together. Each organism depends on the other so they can survive - the fungus gets food from the algae, and the algae gets protection.

Lichens can be important sources of food for invertebrates which in turn support other animals living in the woodland. Humans have also made use of lichens in the past, using them for dying wool and decorations, and in the preparation of cough mixture, perfume, antibiotics and even as food.

Many lichens are very sensitive to air pollution and as a result some are used as indicators of how clean or otherwise the air is. Because of their sensitivity, a lot of species have declined in Britain since the Industrial Revolution with the increase in use of fuels such as coal.