Lichen (Usnea subfloridana)
Of these lichens this 'spidery' one forms great masses of bristly offshoots. It is called Usnea subfloridana.
The Usnea range of lichen are members of the fruiticose set because they produce little fruiting bodies that often look a little bit like golf tee pegs.
Usena subfloridana is by far the most common of the British Usnea species. It grows on trees, fences and occasionally on rock. It is the most tolerant of the species to air pollution and is very common in the south and west of England (including Dorset of course) but it has disappeared from the Midlands and north of England.