Tree lungwort lichen

It is a foliose lichen and its leaf-like thallus is green, leathery and lobed with a pattern of ridges and depressions on the upper surface. Bright green under moist conditions, it becomes brownish and papery when dry. This species often has a fine layers of hairs, a tomentum, on its lower surface. The cortex, the outer protective layer on the thallus surface, is roughly comparable to the epidermis of a green plant. The thallus is typically 5–15 centimetres (2.0–5.9 in) in diameter, with individual lobes 1–3 centimetres (0.39–1.18 in) wide and up to 7 cm long.[4] The asexual reproductive structures soredia and isidia are present on the thallus surface. Minute (0.5–1.5 mm in diameter) cephalodia—pockets of cyanobacteria—are often present on the lower surface of the thallus; these spots are conspicuously darker than the green surface of the thallus.[5] Like other foliose lichens, the thallus is only loosely attached to the surface on which it grows.-Wikipedia