Stereocaulon vesuvianum var. vesuvianum Pers.
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.
Smith et al. editors (2009) The Lichens of Great Britain and Ireland
Dobson (2018) Lichens: an Illustrated Guide to the British and Irish Species