Diploschistes muscorum (images of British lichens)

Initially a parasite on Cladonia species, commonly C. pocillum, or on Stereocaulon, killing the host and taking over the algae, then extending as a thick, uneven to warted, white to pale grey crust; apothecia with black but grey-pruinose, sunken disks and thick margins. Widespread but local, on calcareous soil, including dunes and soil caps on walls, frequently overgrowing mosses.

Refs: Smith et al. (2009), 380; Purvis et al. (1992), 237; Dobson (2005), 166; Dobson (2011), 172; Jahns (1983), 256-257 (photo, printed with strong colour cast in my copy); van Herk & Aptroot (2004), 172-3 (photo); Wirth (1995), 1: 379 (photo); Wirth et al. (2004), 184 (photo); Hansen & Anderson (1995) 88 (photo); Thomsom (1997), 217; Brodo et al. (2001), 304 (photo).

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Images of British Lichens