Lungwort lichen

Description:

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. Photobionts[edit] The thallus contains internal structures known as cephalodia, characteristic of three-membered lichen symbioses involving two photobionts (the photosynthetic symbionts in the fungal-algal lichen relationship). These internal cephalodia, found between the "ribs" of the thallus surface, arise when blue-green algae (from the genus Nostoc) on the thallus surface are enveloped during mycobiont growth.[6] Structurally, cephalodia consist of dense aggregates of Nostoc cells surrounded by thin-walled hyphae—this delimits them from the rest of the thallus which contains a loose structure of thick-walled hyphae.[7] Blue-green cyanobacteria can fix atmospheric nitrogen, enhancing nutrient availability for the lichen. The other photobiont of L. pulmonaria is the green algae Dictyochloropsis reticulata.[8]-Wikipedia

Habitat:

Found along a trail in a maple, fir and cedar dominate forest.

Notes:

The third pic is the back side of the same one.