Lobaria pulmonaria (L.) Hoffm.
Thallus foliose, potentially exceeding 25 cm across, lobes strap-shaped, 1-3 cm wide, more or less dichotomously branched, apices sinuate-indented, upper surface glossy, wrinkled, reticulate and embossed-like, warted with isidia-shaped soralia, mostly marginal or on veins, grey-greenish, pale green when moist, brown-kaki when dry, lower surface slightly tomentose, pale beige to brownish with whitish sections towards veins. Apothecia rare, 2-4 mm diam., disc brown-red, exciple thin. Sometimes free cyanobacteria (Nostoc) are present, Collema-like, on or below the lobe surfaces. This species may simultaneously have a green algae photobiont (Dictyochloropsis) and cyanobacteria within internal cephalodia. Ascospores fusiform to narrowly ellipsoid, (1-) 3 (-5)-septate, 18-30 x 5-9 µm. Medulla: C-, K+ yellow-orange, KC+ yellow-orange, Pd+ orange. Not especially maritime, on mossy trunks and main branches of deciduous trees, often in height, seldom at the base, in oceanic humid woodlands. May also be found on rocks in aerohaline heathlands where this species is a marker of the primeval forest. Sometimes parasited, as closely related species, by Plectocarpon lichenum and then visible as black galls.
This species, strongly in decline, is protected in Finistère, all harvesting is strictly prohibited by Prefectural Decree No. 2012173-0009 of June 21, 2012.