A 'reindeer lichen' which forms mounds of delicate podetia, that are dichotomously branched at the tips and curl down in the same direction. Found on dunes, moors and heathland. C. ciliata var. tenuis, with usnic acid, is very variable - the podetia are greenish grey to yellowish (usnic acid).

References: 
Smith, C.W. et al. editors (2009) The Lichens of Great Britain and Irelandd
Ahti, Stenroos & Moberg. editors (2013) Nordic Lichen Flora. Volume 5 Cladoniaceae