Foliose lichen

Thallus: foliose to subfruticose, up to c. 3 cm across [up to 8-15 cm elsewhere], thin (< 1 mm thick), papery lobes: few to numerous, upcurved, up to 2-5 (-20) mm wide; margins "ragged" [elsewhere sometimes branched and divided into fruticose lobes] upper surface: whitish, whitish green, pale blue-greenish gray, to pale greenish tan (turning green to olive or greenish gray or tan when wet), or occasionally tinged with yellow or reddish, often with darkened areas, shiny to matt, smooth or becoming incompletely and inconspicuously wrinkled to strongly reticulately wrinkled, without distinct pseudocyphellae but ± maculate in places soredia: initially white and granular, sometimes becoming brown and isidioid (simple to coralloid), often in laminal, rounded to irregular soralia or marginal, crescent-shaped soralia upper cortex: c. 15-25 µm thick medulla: white, c. 60-200 µm thick, I+ lavender lower cortex: 16-25 µm thick; rhizines: absent to few ( to many), brown or black, simple or branched lower surface: jet black towards center, or irregularly mottled or spotted brown or white towards the margins; shiny, smooth or reticulately wrinkled and coarsely and sometimes foveolate Apothecia: very rare, 0.5-1 cm broad, marginal, perforate or not; without algae below; hymenium: 34-56 µm; "subhymenium" 16-52 µm, I+ lavender to bright purple asci: clavate, I+ blue or blue-green, 8-spored ascospores: hyaline, simple, ellipsoid to ovoid, 3.5-8.5 x 3-5 µm Pycnidia: not seen Spot tests: cortex K+ yellow, C-, KC-, P+ yellow; medulla K-, C-, KC-, P-, UV- Secondary metabolites: cortex with atranorin and chloroatranorin; medulla with caperatic acid. Substrate and ecology: on trees (usually conifers) or shrubs, or wood, occasionally on rocks and rarely soil; in open woods .