Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Thallus: crustose-areolate areoles: 0.5-2 mm wide, up to 0.75 mm thick, ± angular, surface: black, tessellate due to vertical growth of slender, elongated, densely aggregated lobules [50-75(-100) µm long] anatomy: densely reticulate, almost paraplectenchymatous lower side: attached to the substrate by thick bundles of rhizohyphae Apothecia: immersed to sessile, zeorine, 1-3 per areole, up to 0.75 mm wide; disc: dark reddish, flat, sometimes umbonate, thalline margin persisting, thin, often somewhat crenulate or nodulose; exciple: thin but distinct, up to 15 µm wide, faintly yellowish-brown colored; epihymenium: reddish-brown; hymenium: up to 125 µm high, hyaline, amyloid; paraphyses: distinctly septate, sparingly branched and anastomosing, apically often richly branched and cells distinctly moniliform, up to 5 µm wide and yellowish-brown colored; hypothecium: sometimes elongated as a stipe asci: 8-spored ascospores: simple, hyaline, broadly ellipsoid, (12.5-) 15-17.5 (-20) x 7.5 (-10) µm; walls: thin Pycnidia: immersed, globose to broadly pyriform, 0.075-0.1 mm in diam. conidia: cylindrical, 3 x 1 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on limestone in sheltered, steep or exposed faces of boulders in rocky slopes in chaparral and woodlands World distribution: SW North America and Bermuda Sonoran distribution: limestone deposits in central Arizona and southern California. Notes: The Sonoran material matches all features of S. bermudana except that stroma were not found. The species also resembles species of Psorotichia and Porocyphus from which it is distinguished by the tessellate surface of its areoles (best seen at a higher magnification, 40x) and the rather large size of its areoles. Paulia gibbosa has a similar tessellate surface and surface areoles of the same size, but differs in its loosely reticulate anatomy with larger photobiont cells (>10 µm), the larger, bulging, peltate squamules (4-6.5 mm wide), the smaller apothecia (up to 0.3 mm wide) and its type of ascoma development.