Lichen (Hypogymnia physodes)
This a lichen species that is not affected by pollution at all and can grow just about anywhere, even in parks in cities! It is very common on tree branches and twigs, rocks, walls, even soil.
It can form large, condensed patches of these 'fingery' grey or, sometimes, grey-green lobes or thallus. The underside is much darker being brown at the edges becoming darker still towards the centre.
Find out more about the nature of Dorset at my website www.natureofdorset.co.uk