Images of British Lichens
Punctelia borreri (Sm.) Krog
(= Parmelia borreri (Sm.) Turner)
Thallus foliose, grey, sometimes with brownish or yellowish tinges, underside black (may be paler near the margin), lobe surfaces with scattered, white dots (pseudocyphellae) that extend more or less to the lobe margins and later develop into round soralia; apothecia rare. On nutrient-rich tree bark, less often rocks, predominantly in southern England and south Wales but said to be becoming more frequent outside this range.
Refs: Van Herk & Aproot (2000) Lichenologist 32: 233-246 (photo, fig. 15, and useful comments); Purvis et al. (1992), 428 (as Parmelia); Smith et al. (2009), 769; Dobson (2005), 374 (photo); Dobson (2011), 377-8 (photo); Whelan (2011), 135 (photo); van Haluwyn et al. (2009), 102-3 (photo); van Herk & Aptroot (2004, 2013), 324-5 (photo); Valcárcel et al. (2003), 266-7 (photo, as Parmelia); Frahm et al. (2010), 145 (photo); Wirth, Hauck & Schulz (2013), 2: 808, 958 (photo); Lichen Atlas of the British Isles 1: 985 (1995) (as Parmelia).
Differs from the very similar but generally more common P. subrudecta in its black underside and in its chemistry.
|Pembroke, Pembrokeshire, May 2009|
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Uploaded March 2010, last updated December 2013