Lichen in Cumbria

LICHENS IN CUMBRIA

These curious "plants" - a symbiosis of a fungus and an algae - are perfectly suited to Cumbria. Its moist Atlantic air, clean atmosphere and huge variety of habitat material, make this one of the finest counties for lichens. Because they absorb moisture and nutrients from the air they are important indicators of pollution, especially radioactivity and sulphur dioxide.
On the mountain summits lichens are often the most abundant plant species, although it has to be said that these are often very similar grey crustose varieties found on the rock surfaces. Lower down the slopes, on the more sheltered crags, the foliose species become more prominent and Langdale even has one which is at its only British station.
The upland and lowland bogs have their own range of species, not least of which are the many similar ones belonging to the Cladonia genus.
In the lowland hills the acidic slates and alkaline limestone each attract a different range of species, the latter often having numerous crustose micro-lichens. On walls where mixed stone is used the different colonies of lichen flora are immediately obvious, even to the casual observer, from their different colours and shapes.
In woodland the tree surface is key, each species of tree having different texture, pH and water-retention in its bark. Ash, Sycamore, and Elm are generally good for species; birch and conifers are generally poor. Old woodland is best for tree lichens like the Usnea species, often referred to as Old Man's Beards, although at Hawshead one isolated bush on the road to Colthouse is covered from head to foot with a tree lichen. The smooth bark of Hazel and Beech often hold the Graphis species, so called because their thin pale thalli are covered in black, branched fruiting bodies which look like hieroglyphics.

There are very few species I can actually identify! However they are interesting and challenging subjects to photograph and a selection is offered below that illustrate the comments above - names should be regarded as speculative and any help with identification will be gratefully received!