Hypotrachyna endochlora (Leight.) Hale
Parmelia endochlora Leight.
Parmelia xanthomyela Nyl.
Thallus not very adherent to its substrate, 5-10 cm in its greatest length, formed of branched lobes 2-5 mm in width separated by rounded sinuses. Upper surface dark glaucous gray if humid, paler if dry with small paler or whitish areas, cortex often scuffed and typically showing the pale lemon yellow medulla, laminales, terminal soralia, sometimes capitifiform, grayish to yellowish, floury soredia, face lower black, shiny, with rhizines, long, very branched, often overflowing. Apothecia rare, laminate, pedunculate, 4-7 mm in diameter, disc concave, border crenate thalline. Simple, elliptical spores, 15-19 x 10-12 µm. Cortex: K + yellow; medulla: C + orange, K-, KC + orange, P-. Thermophilic species, saxicolous on acidic rocks but sometimes corticole in the Armorican Massif on the bark of Quercus of wooded heathlands.