Xanthoria elegans (Link.) Th. Fr. subsp. elegans var. elegans
Thallus tightly appressed, composed of radiating long lobes, divided close to margins, rosette-forming, 3-5 cm diam., (or more), lobes narrow, 0.5-1 mm wide, markedly convex, upper surface smooth, bright orange to red-orange, vermilion, yellow-orange, more or less spotted with minute paler dots (visible only with magnifying lens). Apothecia usually numerous, mainly towards thallus center, sessile, 0.5-2 mm diam., disc flat, smooth, persistent, concolourous to the thallus. Ascii 8-spored, 50-60 x 15-22 µm. Ascospores colourless, broadly ellipsoid, polarilocular, 9-16 x 5-9 µm. Photobiont: chlorococcales. C-, K+ purple, KC+ purple, Pd-. Saxicolous, thermophile, heliophile, montane, on more or less calcareous rocks, also on weakly acid rocks notably nutrient-rich perching birds rocks, seldom on artificial substrata. Not to be confused with less brighter Caloplaca species with shorter and less convex and less crowded lobes, potentially pruinose, devoid of lower surface cortex (see notably Caloplaca biatorina sharing a common habitat). See also Xanthoria resendei , very close, but more robust and found on Mediterrranean coastal rocks, notably in islands.