Parmelia omphalodes (images of British lichens)

Thallus foliose, yellowish brown to dark brown, grey- or green-tinted when shaded or wet, with conspicuous, white pseudocyphellae on the lobe surfaces; medulla orange-red with potassium hydroxide; apothecia with dark-brown discs and pale, crenulate margins. Locally common in the north and west, on exposed, base-poor rocks.

Refs: Smith et al. (2009), 652; Purvis et al. (1992), 425; Dobson (2005), 302 (photo); Dobson (2011), 304 (photo); Jahns (1983), 196-7 (photo); Allen (2007), 24 (photo); Whelan (2011), 121 (photo); van Herk & Aptroot (2004), 276-277 (photo); Hansen & Anderson (1995), 45 (photo); Moberg & Holmåson (1984), 91 (photo); Holien & Tønsberg (2008), 56 (photo); Nordic Lichen Flora (2011) 4: 85, 162 (photo, as P. omphalodes subsp. omphalodes); Puntillo (1996), plate 28 (photo); Brodo et al. (2001), 482 (photo); Hinds & Hinds (2007), 337-8 (photo); Lichen Atlas of the British Isles 1: 1006 (1995).

Can be confused with P. discordans (q.v.) and best confirmed by chemical tests (medulla K- in P. discordans, but cortex K+ yellow in both species); beware also of old and brown states of P. sulcata and P. saxatilis (latter strongly isidiate).

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Images of British Lichens