Caloplaca aurantia (images of British lichens)

Thallus egg yellow to orange, placodioid (i.e. a crust but lobulate at the margins), often (as in related species) with a whitish zone at the base of the lobules and with the interior of the thallus often yellow-brown, lobules markedly flattened as if ironed; apothecia deeper orange to orange-brown and crowded in the centre of the thallus. Generally on limestone rocks and stonework, predominantly in south-eastern England but extending west on sunny, limestone outcrops.

Refs: Gaya (2009), 108, 187 (photo); Smith et al. (2009), 255; Purvis et al. (1992), 146; Dobson (2005), 96 (photo); Dobson (2011), 105 (photo); Whelan (2011), 57 (photo); van Herk & Aptroot (2004), 88-89 (photo); Wirth (1995), 1: 216, 221 (photo); Wirth et al. (2004), 234 (photo); Puntillo (1996), plate 8 (photo); Lichen Atlas of the British Isles 6: 239 (2001).

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Images of British Lichens