Parmeliopsis ambigua (images of British lichens)

A neat little lichen, lobes flat, adpressed, usually radiating, approx. 1mm wide, yellow-green, lustrous, usually with rather conspicuous, flat to convex, laminar soralia. Primarily a species of conifer wood in central and eastern Scotland, but became much more widespread and more general on acidified substrates as a result of sulphur dioxide pollution, now contracting in range again as SO₂ levels have dropped.

Refs: Smith et al. (2009), 660; Purvis et al. (1992), 250 (as Foraminella ambigua); Dobson (2005), 308-309 (photo); Dobson (2011), 310 (photo); Jahns (1983), 204-5 (photo); van Haluwyn et al. (2009), 108-9 (photo); van Herk & Aptroot (2004), 280-281 (photo); Hansen & Anderson (1995), 47 (photo); Wirth (1995), 2: 671-672 (photo); Wirth et al. (2004), 113 (photo); Frahm et al. (2010), 125 (photo); Moberg & Holmåson (1984), 98 (photo); Holien & Tønsberg (2008), 61 (photo); Nordic Lichen Flora (2011) 4: 93, 163 (photo); Pope (2005), 36 (photo); Brodo et al. (2001), 489 (photo); Walewski (2007), 117 (photo); McCune & Geiser (2009), 228 (photo).

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Images of British Lichens