A common but colourful lichen

March 14th 2019

Helen Lockhart took a photograph of this lovely orange lichen on her smartphone on 20th January 2018 and later showed it to me.  It was on the roadside wall of the old burial ground at Stoer (NC0428).

The species is Xanthoria parietina, once known as Yellow Crotal.  It was gathered, in the past, to produce dyes in a wide range of colours, both browns and in the pink/purple/blue range.

Although one of the commonest leafy (foliose) lichens in the British Isles, it is amongst the most colourful and worth a second look.  It is unusually resistant to sulphur dioxide pollution and has a positive preference for nutrient-rich sites with high nitrogen levels, such as bird perches.  Away from these, it occurs commonly in coastal areas and also inland on trees like elder which have alkaline bark.  

In shady sites, the orange pigment may not develop and an underlying grey-green colour shows through.  Occasionally, as here, the thallus is multicoloured even in plants in full sun.  The large flat-topped fruiting bodies, or apothecia, show well in this photograph. They generate the spores of the fungus in the symbiotic partnership with an alga or cyanobacterium which constitutes a lichen. 

Ian M. Evans

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Recent Sightings

Gannet

Eight birds fishing, Bay of Stoer (Charlie Leeson) (10/08)

Corncrake

Single bird heard, Culkein Stoer (Nick Simpson).   (09/08)

Merlin

Single male flying alongside road, Inchnadamph (Paul MGowan) (09/08)

Common Toad

Single amphibian in grass near Oldany (DAH) (07/08)

Palmate Newt

Single amphibian in grass near Oldany (DAH) (07/08)

Butterflies

Scotch Argus (7), Speckled Wood (2), Dark Green Fritillary (1), Meadow Brown (1), all along stretch of B869 from mouth of Oldany River to Culkein Drumbeg junction (DAH) (07/08)

Gannet

Two birds, one immature, fishing from Bay of Clachtoll to Bay of Stoer (Charlie Leeson) (07/08)

Field Gentian (Gentianella campestris)

15+ plants coming into flower, Stoer green (Charlie Leeson) (07/08)

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