[Squamarina degelii Frey & Poelt]
Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: squamulose or placodioid, areolate centrally, forming irregular but distinct rosettes or mounds, 0.51(-1.5) cm wide, 1-2 mm thick, sometimes confluent, rather closely appressed; prothallus: absent squamules: broadly rounded, thick, subpeltate, fastened by a wide hyphal cluster, 0.5(-0.8) mm across, plane to slightly concave; edges often somewhat raised up and thickened lobes: distinct, separate, 1.5-2(-3) mm long, 0.5-1.5 mm wide, mostly somewhat longer than wide, c. 0.3 mm thick, broadly rounded to coarsely and irregularly crenate to deeply divided into 1 mm wide, mostly rounded segments, plane to slightly convex; tips: distinctly free from the substrate; margin: often somewhat bent upwards and thickened upper surface: pale to grayish green-yellow or pale yellowish green, often pale yellow to white (pruinose) on edges of squamules or lobes (in herbarium yellowish gray under pruina, to almost yellowish white with pruina), sometimes somewhat rimose, epruinose to thinly white pruinose, esorediate upper cortex: with relatively sparse empty algal cells, (25-)40-50 µm thick, strongly inspersed with granules (soluble in K); hyphae: strongly conglutinate, evenly thick to rather irregular, distinctly delimited, with swollen hyphae medulla: dense, filled with large grayish granules (insoluble in K); algal layer: continuous, dense, distinctly differentiated, (30-)50-60 µm thick; often interrupted by anticlinal hyphal bundles lower surface: white lower cortex: with rather weakly conglutinate, +randomly oriented to anticlinal hyphae 2-3 µm in diam. and with thread-like lumina, c. 40 µm thick Apothecia: dispersed to entirely covering the thallus center, immersed to broadly emergent, then soon broadly sessile, finally constricted, 1-1.5(-2.5) mm in diam., at first rounded, later distorted (sinuous) and lobed disc: pale to medium yellow to yellowish brown or olive, plane to moderately convex or when old undulate and funnel-form deepened in the middle, epruinose, dull margin: concolorous with thallus, sometimes white and pruinose, thin, 0.2-0.3 mm wide, often irregularly broadened and crenate towards inside, at first somewhat projecting, then level or finally +crowded, sometimes with a grayish green-yellow parathecial ring visible when young amphithecium: present, with a continuous to interrupted algal layer (50-75 µm thick) in upper part of margin and extending under the hypothecium, without crystals, corticate; cortex: similar to that of thallus, 30-50 µm thick parathecium: hyaline, with conglutinated, periclinal to randomly oriented hyphae c. 3 µm in diam. and with narrow lumina mostly 1-2 µm wide epihymenium: inspersed with fine brownish granules (soluble in K), covered by thin surface layer, (10-)15-20(-25) µm thick hymenium: hyaline, distinctly delimited, (40-)60-70(-80) µm high; paraphyses: often anastomosing, strongly conglutinate; tips: hyaline, only weakly clavate, up to 3 µm thick; subhymenium: well delimited, 10-15 µm thick; hypothecium: 30-75(-100) µm thick asci: clavate, 8-spored ascospores: hayline, simple, ellipsoid to broadly ellipsoid, 8-9.5(-11) x (4-)5-6(-7) µm Pycnidia: not seen Spot tests: thallus K-, C- KC-, P-; cortex KC+ yellow; medulla KC- Secondary metabolites: cortex with usnic acid; also isousnic acid as a minor substance; medulla with roccellic acid, or apparently no substances. Substrate and ecology: in dry, open situations on +calcareous rocks (calcareous slate, schist, or sandstone; limestone) at 600-4000 m World distribution: Europe (see maps in Poelt and Krüger  and Timdal ); Asia (Himalayas) and SW U.S.A. Sonoran distribution: Arizona, on sandstone at 1625 m. Notes: The presently known distribution of Lecanora neodegelii is very peculiar, and the ecology is quite different in the different areas from which it has been reported. The thallus is very uniform except in the amount of gray-white tone; the disc vary from pale to dark ochre and be concave to convex and round to almost lobed, and the margin varies in the amount of crenation; the spores vary from round to ovoid. It is similar to see L. kofae, which grows in Sonoran Desert scrub, and differs in that the thallus flattened and distinctly rosulate, with cortical hyphal bundles dividing the algal layer, few or no dead algae in the cortex. Also see under L. arenisaxicola, L. kofae, and L. valesiaca for comparisons with those species. The transfer of Squamarina degelii to Lecanora is because the species of Squamarina sect. Petroplaca Poelt have a different ascus type from Squamarina s. str., and show greater affinities to the species presently treated under Lecanora subg. Placodium.