Lobaria pulmonaria is a ample epiphytic lichen consisting of an ascomycete bane and a blooming algal accomplice active calm in a accommodating accord with a cyanobacterium—a symbiosis involving associates of three kingdoms of organisms.
It is a foliose lichen and its leaf-like thallus is green, coriaceous and lobed with a arrangement of ridges and depressions on the high surface. Bright blooming beneath clammy conditions, it becomes brownish and chiffon if dry. This breed generally has a accomplished layers of hairs, a tomentum, on its lower surface. The cortex, the alien careful band on the thallus surface, is almost commensurable to the covering of a blooming plant. The thallus is about 5–15 centimetres (2.0–5.9 in) in diameter, with alone lobes 1–3 centimetres (0.39–1.18 in) advanced and up to 7 cm long.The asexual changeable structures soredia and isidia are present on the thallus surface. Minute (0.5–1.5 mm in diameter) cephalodia—pockets of cyanobacteria—are generally present on the lower apparent of the thallus; these spots are clearly darker than the blooming apparent of the thallus. Like added foliose lichens, the thallus is alone about absorbed to the apparent on which it grows.