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(Map updated: 11 August 2009)

This large yellow-brown, non-isidiate former ‘Parmelia’ species forms large patches on siliceous maritime rocks and cliffs. Look for it in the ‘grey’ zone. Lower surface black except near the lobe ends, upper surface with patchy white blotches. Spot tests: cortex K-, medulla Pd-. Close to X. pulla but thallus yellower and uniformly paler.

Key characteristics

• Thallus large foliose, non-isidiate, yellow-brown – with some white blotching – lower surface black except for the edges; cortex K-
• On sea cliffs in the ‘grey’ zone.

Original text submitted by Vince J. Giavarini