Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Life habit: lichenized Thallus: large foliose, rarely small to almost squamulose, approximately circular in outline, (1-)2-30 cm in diam., sometimes forming extensive mats among mosses that may extend for several meters, usually lobate lobes: +flattened and elongate (5-15 mm wide and up to 5 cm long), often dichotomously branched, imbricate or separate; tips: rounded to subtruncate, often ascending upper surface: gray, bluish gray, grayish brown to brown when dry, bluish gray, blackish green or bright green when wet, smooth, dull or shiny, +scabrid, tomentose or pruinose; with or without isidia or soredia upper cortex: paraplectenchymatous medulla: white, +loosely interwoven hyphae photobiont: primary one usually Nostoc but a few species with the chlorococcoid green alga (Coccomyxa) and then with Nostoc as a secondary photobiont in cephalodia lower cortex: absent lower surface: brownish white, densely arachnoid-tomentose or with anastomosing pale or dark brown to black veins, rhizinate; rhizines: white, brown or black, simple, bushy or fasciculate Ascomata: apothecial, frequent, ovoid, semi-immersed, marginal, often at lobe tips or on ascending lobules, up to 10 mm in diam., hemiangiocarpic; margin: smooth to crenulate disc: saddle-shaped, flat or oval, red-brown to black, smooth, paler marginally true exciple: paraplectenchymatous, 100-135 µm wide, marginal cells with short hairs hymenium: brown above, colorless below, K-, I+ blue; paraphyses: septate, simple, 2-3 µm wide, +swollen at the apices and pigmented asci: cylindrical, fissitunicate, Peltigera-type, the apex of the endoascus with a K/I+ blue annulus, 8-spored ascospores: fusiform to acicular, colorless, 3-many septate, 25-75 x 3-7 µm Conidiomata: pycnidial, brown above, pale below, immersed, up to 2 mm in diam. conidia: bacilliform or slightly bifusiform, colorless, simple, 4-10 x 2-4 µm Secondary metabolites: hopane triterpenoids and tridepsides or none detected Geography: world-wide in moist habitats, especially cool temperate ones in North and South America, Europe, Asia, Australasia and Africa Substrate: most often on soil and among mosses over rocks, rarely on tree trunks.