Xanthoparmelia stenophylla (Ach.) Ahti & D. Hawksw. chémo stenophylla

    Thallus foliose, irregularly spread out, up to 20 cm wide, loosely attached, made of narrow or broad lobes mixed up, upper surface convex, pale greyish tinged with yellow, pale yellowish, more or less black-spotted, no isidia nor soralia, lower surface pale brown-black with rhizines. Apothecia slightly stalked, concave, 2-8 mm diam., disc brown-red, exciple thin. Pycnidia in general numerous and clearly visible as black dots. Photobiont : trebouxioide. Medullae : C-, K+ yellow then red, Pd+/- orange. On well-lit rocks and notably on horizontal surfaces. N.B. It seems that under this name, different taxa are taken into account, and especially near the sea shore; these taxa have been taken for different by several authors; some resemble to Xanthoparmelia conspersa but without isidia, others to the pale  Xanthoparmelia pulla ; these taxa would deserve a specific research. We have done an exception with Xanthoparmelia stenophylla chémo protomatrae that is K+ brownish and, to our knowledge, the far most frequent taxon near the sea shores (the discrimination proposed here is new).*