Parmelia omphalodes (L.) Ach.

    Thallus foliose, rosette-forming, to 15 cm diam., lobes narrow, 1 (-3) mm wide, loosely attached, lobe apices angular and slightly palmate, upper surface conspicuously covered with a network of pale to whitish lines of pseudocyphella, rounded to elongate, brown-greenish, dark brown, dark grey-brown, greyish when shaded, tinged silvered, lower surface blackish with simple or forked rhizines towards the margin. Apothecia rare, cup-shaped, to 10 mm diam., disc dark brown-red, exciple paler. Ascospores simple, ellipsoid, 10-15 x 7-9 µm according to the literature; (10) 12-17 x 7-9 µm according to our measurements. Cortex: K+ yellow. Medulla C-, K+ yellow-reddish, KC+ orange, Pd+ orange. In principle montane, but also may grow on acid siliceous rocks in heathlands, near the seashore this species most often is brown and looks like burnt by the seaspray, but the white lines of the network are still visible. If the thallus is evenly dark brown with very few pseudocyphella, mostly marginal, see Parmelia discordans.

N.B. Several taxa difficult to distinguish would be brought together under this name.