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Xanthoria polycarpa (Hoffm.) Th. Fr. ex. Rieber



Habitat: Ubiquitous


    Thallus foliose, rosette forming, 3 cm diam. max., made of lobes, enlarged and incised at tips to form short finger-like lobules less than 1 mm wide, upper surface bright yellow-orange, brigth yellow, but grey-glaucous when shaded, lower surface whitish with small holdfasts. Thallus often obscured by the numerous crowded sessile to almost stalked apothecia, sometimes covering or extending the margin,  more or less distorded by their neighbours, 1-3 mm diam., disc flat dark orange to brown-orange, margin thick, sinuous pale and prominent becoming somewhat crenulate when mature, concolourous or slightly paler than the thallus. Ascospores plurilocular, ellipsoid, 11-15 x 6-8 µm. Medullae : C-, K+ purple, KC-, Pd-. Rather rare in our prospection area, typically growing at branch points of deciduous trees or small branches, notably in urban areas. Rare on cement walls of pigsties and in that case in combination with Xanthoria parietina. Easily confused with Xanthoria parietina that is much more common; althought they can grow together, Xanthoria parietina is larger and without almost stalked crowded apothecia covering the whole thallus.*

Xanthoria polycarpa avec Teloschistes chrysophthalmus Pointe du Guern

Xanthoria polycarpa Pays basque Col d'Iraty 1

Xanthoria polycarpa Belgique 2
Jacques HAINE

Xanthoria polycarpa Belgique 1
Jacques HAINE

Xanthoria polycarpa Belgique 3
Jacques HAINE

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