Parmotrema crinitum (Ach.) M. Choisy forme saxicole.

    Thallus foliose, loosely attached to the substratum, to 15 cm across, lobes to 1-1.5 cm wide, margins sometimes indented, tips rounded, upper surface and margins with numerous black cilia, 2-5 mm long and numerous cylindrical or coralloid isidia, notably towards the center, grey-glaucous, grey-greeenish, pale grey-blue, but sometimes pale yellowish, see: Parmotrema crinitum forme saxicole jaunâtre; lower surface with simple rhizines, dark brown towards the margin, center darker. Apothecia rare, 3-8 mm diam., sessile or more or less stalked, disc brown, exciple crenulate and isidiate. Ascospores colourless, simple, broadly ellipsoid, slightly curved, 21-31 x 11-15 µm. Cortex: C-, K+ yellow, KC-, P-; medulla: C-, K+ yellow to orange, KC+ yellow-orange, P+ yellow-orange; UV-. Species growing on the mossy trunks of oceanic forests but more frequent, although localized, on rocks (or at their base in the heath) of the areohaline zone because this species has strong maritime and oceanic affinities, see Parmotrema crinitum forme corticole

N.B. Not to be confused with Parmelinopsis horrescens  which is smaller, medulla K+ yellow, and with smaller lobes, less indented but with more abundant isidia and Pd-.