Tephromela atra (images of British lichens)

Thallus crustose, pale grey, cracked-areolate and warted, looking much like fossilised porridge; apothecia conspicuous and usually abundant, discs black, rims grey-white and crenulate, hymenium with purplish colours in section. Throughout the country on hard, exposed rocks, often dominant on coastal rocks but also common inland.

Refs: Smith et al. (2009), 876; Purvis et al. (1992), 591; Dobson (2005), 422 (photo); Dobson (2011), 428 (photo); Jahns (1983), 206-7 (photo, as Lecanora atra); Allen (2007), 35 (photo); Whelan (2011), 145 (photo); van Herk & Aptroot (2004), 358-9 (photo); Wirth (1995), 2: 891, 893 (photo); Wirth et al. (2004), 208 (photo); Moberg & Holmåson (1984), 112 (photo, as Lecanora atra); Brodo et al. (2001), 676-7 (photo); Øvstedal & Lewis Smith (2001), 324, plates 82 & 83 (photos); Thomson (1997), 603.

Easily confused with Lecanora gangaleoides, with which it may grow, but L. gangaleoides typically has a slightly darker, sometimes greenish tinted thallus, orange colour in the lower medulla (pick away the surface) and it lacks the purple colours internally in the apothecia.

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Images of British Lichens