Pertusaria aspergilla (images of British lichens)

Thallus rather thin, grey, cracked-areolate, characterised by the small and rounded ('punctiform') soralia scattered over the surface; apothecia unknown. Best separated from similar species by chemical tests. Widespread, locally common on exposed, base-poor rocks in the north and west.

Refs: Smith et al. (2009), 678; Purvis et al. (1992), 452 (as P. dealbescens); Dobson (2005), 323 (photo); Dobson (2011), 324 (photo); Whelan (2011), 127 (photo); Wirth (1995), 2: 696.

lastdragon.org

Images of British Lichens