Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: crustose to +placodioid, rimose-areolate to areolate, rosulate, usually forming distinct rosettes 1-2(-4) cm in diam., 0.1-0.5(-1) mm thick, plane to slightly thickened in center; sometimes coalescing, sometimes scattered and irregular; usually closely and completely adherent to the substrate; prothallus: absent areoles: contiguous, 0.5-0.7 mm across, plane lobes: plane to convex (flattening towards periphery), 1-2(-5 mm) long, usually clearly radiating, moderately crenate-incised, the ultimate segments 0.3-0.7 mm wide; edges: towards tips, often raised or thickened, forming rims upper surface: pale greenish yellow but densely pruinose throughout, appearing yellowish white, extreme tips of lobes sometimes blackening, esorediate upper cortex: without dead algal cells, rather distinctly delimited, 20-30 µm thick, with strongly swollen hyphal tips, without distinct conical hyphal bundles, inspersed almost throughout with grayish crystals (insoluble in K) which also cover the surface; epinecral layer: not evident medulla: thin, moderately dense, thickly inspersed with grayish granules (insoluble in K), with thick-walled, +randomly oriented hyphae 3-5 µm in diam. and with thread-like lumina; algal layer: +uniformly c. 50 µm thick, continuous to interrupted lower cortex: absent or poorly developed lower surface: pale Apothecia: common, semi-immersed then becoming sessile and +constricted, 0.5-1.5(-2) mm in diam. disc: usually moderate yellow to pale orange or brown, or (in var. siberica) often at least spottily green and N+ when young and near the margin, becoming olivaceous or yellowish green to greenish black, plane or occasionally convex, sometimes roughened and cracked, +dull, epruinose margin: entire to flexuous or crenate, persistent, level with disc, either without a parathecial ring or with an indistinct, narrow parathecial ring paler than the disc and 0.1-0.15 mm wide cortex: similar to that of thallus amphithecium: present, with an algal layer developed marginally in upper part and extending below the hypothecium, with coarse crystals (insoluble in K) in the medulla, similarly corticate to the thallus parathecium: inner part hyaline to pale yellow and translucent, pol-, outer part opaque and pale gray, pol+, composed of +parallel, conglutinated, +randomly oriented hyphae c. 5 µm in diam. epihymenium: inspersed with fine yellow-brown granules (soluble in K), 10-30 µm thick hymenium: hyaline, 55-70 µm tall; paraphyses: tips: hyaline and scarcely thickened, or (var. siberica) green-black and strongly thickened, up to 2.5 µm thick; subhymenium: pale gray, 30-60 µm thick; hypothecium: bowl-shaped to conical, 30-130 µm thick centrally asci: clavate, 8-spored ascospores: hyaline, simple, ellipsoid to broadly ellipsoid or ovoid-ellipsoid, 9-11 x 5-6 µm Pycnidia: immersed, sometimes common but very small and often inconspicuous, ostiole: pale yellow to green; conidiophores: type III of Vobis (1980) conidia: filiform, mostly curved, 15-20 µm long Spot tests: thallus and apothecia K-, C-, KC-, P-; cortex KC+ pale yellow; discs when at least partly green N+ red-violet Secondary metabolites: cortex with usnic acid; medulla with roccellic acid. sibirica: Poelt, Mitt. Bot. Staatssamml. München 19