Heterodermia leucomela (images of British lichens)

Foliose, with ascending to erect, grey, strap-shaped lobes margined with conspicuous, black cilia, soredia, if present, confined to undersides of the lobes; apothecia unknown in Britain. Amongst coastal rocks or in lightly grazed, cliff-top turf, sometimes with Teloschistes flavicans, now very rarely on trees; formerly in a number of localities in the south but now nationally rare, restricted to a very few sites in south-west England and western Wales, where it depends on continuing appropriate management.
British Red Data Book species: endangered; scheduled protected species, Wildlife and Countryside Act 1981.

Refs: Smith et al. (2009), 431; Purvis et al. (1992), 271 (as H. leucomelos); Dobson (2005), 187 (photo); Dobson (2011), 192 (photo); Jahns (1983), 250-1 (photo, as H. leucomelos, printed too blue in my copy); Church et al. (1996), 46 (as H. leucomelos); Brodo et al. (2001), 338-9 (photo); McCune & Geiser (2009), 138 (photo).

I have followed Smith et al. and other recent authors in using the spelling 'leucomela', but this correction of the original spelling 'leucomelos' is arguable, or at least was based on a now outdated rule in botanical naming, but may be valid for other reasons. Greek adjectival endings are complex!

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Images of British Lichens