References
- Druce , G.C. 1932 . The Comital Flora of the British Isles Arbroath
- James , P.W. 1965 . A New Checklist of British Lichens . Lichenologist , 3 : 95 – 153 .
- James , P.W. 1966 . A New Checklist of British Lichens: Additions and Corrections . Lichenologist , 3 : 242 – 247 .