Forms compact tufts of erect or decumbent grey-white pseudopodetia, branched or unbranched. Small phyllocladia usually with dark grey centres and pale margins. Very variable in form. Common in upland areas on siliceous rocks.

References: 
Smith, C.W. et al. editors (2009) The Lichens of Great Britain and Irelandd
Dobson, F.S. (2018) Lichens: an Illustrated Guide to the British and Irish Species