Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life habit: lichenized, in some cases lichenicolous in young developmental stages Thallus: thickly crustose, rimose-areolate, sometimes placodioid, or subsquamulose areoles: flat or convex to almost bullate upper surface: smooth, dull or subnitid, whitish-gray pruinose, or naked and brown upper cortex: paraplectenchymatous, composed of small roundish-angular cells medulla: white, subparaplectenchymatous lower and lateral cortices: where present as in upper cortex photobiont: primary one a chlorococcoid alga, secondary photobiont absent; algal layer: continuous; the algal cells: ± in columns lower surface: attached with ± constricted bases or stipes, or rhizine-like structures; rhizohyphae: lacking Ascomata: perithecial, laminal, immersed, subglobose; exciple: colorless or brown to black; involucrellum: lacking (or a very reduced apical lid); interascal filaments: absent; ostiolar filaments: present asci: clavate, wall not amyloid, 8-spored ascospores: biseriate, ellipsoid or oblong-ovoid, hyaline, simple or 1-, rarely 3-septate, non-halonate, smooth Conidiomata: pycnidial, laminal, immersed, Dermatocarpon-type conidia: subcylindrical to bacilliform Secondary metabolites: none detected Geography: world-wide, particularly in temperate, semi-arid regions Substrate: calciferous or non-calcareous rock.