Bull. Soc. Linn. Normandie, Sér. 2 4, 2: 158 (1870).
Basionym: Ramalina scopulorum var. cuspidata Ach., Lich. Univ.: 605 (1810).
Thallus: Like a finer form of R. siliquosa, but differing in the more erect, terete, narrower (1-3 mm) main branches which are often markedly shiny-blackened at the base and elsewhere, originating from a wide-spreading holdfast, sometimes forming swards; surface shiny, smooth, brown-yellow or pale green with a yellow tinge. Pycnidia blackened at ostioles.
Chemistry: 3 chemotypes all with usnic acid - medulla (a) K+ yellow-->red (crystals), Pd+ yellow-orange, UV- (norstictic acid), (b) K+ yellow-orange, Pd+ yellow-orange, UV- (stictic acid); (c) K-, Pd-, UV- (no chemistry).
Molecular data: Genbank
Distribution: Database
Note: Numerical taxonomic studies have supported the distinctness of R. cuspidata from R. siliquosa despite the similar morphologies and range of chemotypes. The two species are usually distinguishable when growing together: R. siliquosa has a matt surface, lacks the characteristic + blackened areas, especially at the holdfast and around the pycnidial ostioles and usually has more flattened lobes. R. cuspidata tends to occur in more exposed situations lower down the shore that R. siliquosa - the latter may also occur in inland sites (e.g. Stonehenge, Wiltshire).
Ecology: On wind-exposed, siliceous, seashore rocks, xeric-supralittoral, often with Ramalina siliquosa or somewhat lower on the shore, rarelyon wood of fence posts, coastal.