ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Parmeliaceae

Genus Xanthoparmelia, meaning 'golden yellow Parmelia'

Common name:            Peppered Rock Shield

Synonym:                    Parmelia conspersa

Habitat:                         Montane (for this entry)

Substrata:                     Rocks

Growth form:                Saxicolous

Thallus:                  Foliose

Apothecia:                    Lecanorine

BLS identity rating:        Graded 1/5 (identification should be straightforward)

Thallus forming large rosettes, typically around 10cm dia., sometimes bigger, made up of narrow radiating, overlapping lobes, up to 4mm wide and much divided, with delicate cylindrical coralloid isidia, which may be sparce, but often covering the whole surface; yellow-grey to bluish-grey to greyish-green; underside dark brown to black, paler brown towards the margins, with widely spaced  simple rhizines; normally fertile; apothecia sessile, can be large, up to 1cm dia., disc reddish-brown with a thin, contorted and often isidiate margin.

Common on exposed siliceous rocks, walls and roofs also, in Britain, frequently found on drier rocks in nutrient-enriched streams and lakes. In Austria, where the following specimen was photographed, it is described as "a species found on siliceous rocks wetted by rain, including pebbles near the ground, with a wide altitudinal range; widespread throughout the Alps".