Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: foliose, 3-10(-15) cm in diam., loosely adnate, irregularly lobate lobes: irregular, somewhat elongated, often lobulate, often flabellate or lobulate, +plane, separate, 3-15(-20) mm wide, 100-200 µm thick; apices: rotund, entire to crenate, occasionally upturned upper surface: medium gray to more typically bluish gray, dull to somewhat shiny, somewhat wrinkled internal anatomy: with upper and lower cortices consisting of a single layer of irregularly isodiametrical cells, internally with loosely interwoven chains of Nostoc and hyphae lower surface: pale to medium gray, smooth, with dense white tomentum of cylindrical hairs up to 0.1 mm long Apothecia: frequent, laminal, stipitate, 1-2 mm wide disc: brown to red-brown, plane to convex margin: thalline, concolorous with the thallus, rugulose, often pubescent exciple: euparaplectenchymatous, 20-25 µm centrally hymenium: hyaline below and thinly brown above, 100-130 µm tall; paraphyses: unbranched, 1-2 µm wide, slightly inflated apically; subhymenium: pale yellow, 50-60 µm thick asci: cylindrico-clavate, 8-spored ascospores: hyaline, submuriform, 3-4-septate transversely, 0-1-septate longitudinally, ellipsoid with acuminate ends, 25-35 x 10-12 µm Pycnidia: not observed Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on bark World distribution: North, Central and South America and Japan Sonoran distribution: montane areas of Chihuahua. Notes: Leptogium acutisoporum is somewhat similar to L. rugosum, but the former has a bluer, less strongly wrinkled thallus as well as ellipsoid spores.