Caloplaca verruculifera (images of British lichens)

Thallus greenish- or greyish-yellow to yellow, or infrequently tinged orange, placodioid with marginal lobes usually long and finger-like, pruinose, inner parts of thallus surface becoming covered by dense, globose or flattened-globose isidia; apothecia rare. Generally on nutrient-enriched coastal rocks, often below below sea-bird colonies, in the north and west. Potentially can be confused with C. decipiens, which can occur on coastal rocks, but which is brighter orange and has globose soredia developing from soralia initially on the lobule margins, whereas C. verruculifera has globose isidia developing directly from the thallus surface.

Refs: Smith et al. (2009), 273; Purvis et al. (1992), 158; Dobson (2005), 109 (photo, orange variant); Dobson (2011), 118 (photo, orange variant); Allen (2007), 14 (photo); Dalby & Dalby (2005), 10 (painting), 18 (photo); Moberg & Holmåson (1984), 188 (photo); Thomson (1997), 178 (photo, but description suggests colour variant); Brodo et al. (2001), 205 (photo); Lichen Atlas of the British Isles 6: 286 (2001).

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Images of British Lichens