Caloplaca citrina (images of British lichens)

Thallus greenish yellow to yellow, forming an irregular, areolate crust, areoles sorediate over much of their surface; apothecia with sorediate margins. Very common throughout Britain, including urban areas, on rocks, walls and other artificial substrates such as metal fences. The commonest of a complex of species that includes C. flavocitrina, which is much more likely than true C. citrina to be on bark.

Refs: Arup (2006) (photo); Smith et al. (2009), 259; Purvis et al. (1992), 149; Dobson (2011), 108 (photo); Jahns (1983), 246-247 (photo); van Herk & Aptroot (2004), 90-91 (photo); Thomson (1997), 155; Lichen Atlas of the British Isles 6: 247 (2001). N.B., the brighter orange taxon illustrated in Dobson (2005) under this name is C. dichroa, fide Fletcher & Laundon in Smith et al.

If anyone can identify the millipede, please let me know.

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Images of British Lichens