Thallus: crustose to cushion-like, effuse, cracked or areolate to +verruculose or occasionally bullate or con-volute-rugulose, often very thin but also up to 1.5 mm thick, sometimes delimited by a thin, dark brown, irregular prothallus surface: white to gray or creamy white, smooth or somewhat farinose (pruinose), overlain by an epinecral layer up to 50 µm thick medulla: white, variably thick, composed of mixed and loosely interwoven thin-walled hyphae with many crystals of unknown nature (soluble in K) incorporated among the hyphae Ascomata: numerous, scattered or crowded, rounded (0.25-0.9 mm in diam.) or lirellate (0.8-2 x 0.3-0.6 mm), unbranched, irregularly substellate, at first immersed but then +adnate or sessile, not constricted at base disc: black, plane to convex, whitish or grayish pruinose (C+ red) margin: conspicuous when young, thick, scarcely or not raised above level of disc, covered by +densely white pruina, when old often +excluded exciple: well developed, composed of intertwined, coalescent, dark brown, carbonaceous hyphae, K+ dark green pseudothecium: pale brown, sometimes with a greenish tinge, 25-30 µm thick, gradually paling downward, with pale brown, granular gel, K+ pale olive green, I+ blue, K/I- or + blue in lower part hymenium: hyaline, 55-140 µm tall, I ±pale red K/I+ blue; paraphysoids: 1 µm or less thick below, coherent, sparsely branched and anastomosing, not or slightly widened apically where richly branched, intertwined, brown, 1-2 µm thick, with slightly pigmented walls subhymenium: pale brown, 25-50 µm thick; hypothecium: dark brown-black, carbonaceous, K+ dark olive-green, I-, K/I- asci: clavate to oblong or subcylindrical, I-, K/I+ blue, 50-110 x 13-20 µm, grumulosa-type, with inconspicuous ring, 8-spored ascospores: hyaline, becoming brown only when old, transversely (6-)7(-8)-septate (the locules equal in length), oblong to fusiform, straight or slightly curved, 19-26(-30) x 4-5.5(6) µm, with thin walls and not or slightly widened at the septa, not constricted, surrounded by a thick gelatinous sheath, hyaline but turning brown when old Pycnidia: immersed, dark brown, expanded at tip, secondarily multilocular conidia: hyaline, straight, bacilliform, 5-10 x 1 µm Spot tests: thallus K-, C+ red, KC+ red, P- or P+ pale yellow in parts Secondary metabolites: containing lecanoric and gyrophoric acids, traces of erythrin, and traces of unknowns detected by HPLC but not seen in TLC. Substrate and ecology: on volcanic or calcareous rock, sometimes sandstone, coastal, moderately shaded, usually north-facing, vertical or almost vertical exposures, and underhangs, recesses, small cavities, and roofs of caves, ombrophobic (i.e., in areas sheltered from precipitation) World distribution: western North America (California and Mexico) Sonoran distribution: southern California, Baja California, and Baja California Sur. Notes: Lecanographa hypothallina is a rather variable species. The thallus varies from very thin and areolate to relatively thick and bullate. In some populations, the ascocarps are completely lirelliform, +subsellate, with prominent margin and convex disc; while in others they are +round, immarginate, and with a quite convex disc. The asci and ascospores are also somewhat variable and in some specimens mature asci of 70 x 13 µm and ascospores of 23 x 3.5 µm have been measured. See Egea and Torrente (1989 & 1992) for more details.