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

Thallus: squamulose, composed of imbricate, flattened, minute, 0.1-0.2(-0.4) mm wide squamules, covering substrate, when fully developed incised, with terminal segments shaped like granules (35-100 µm in diam.) surface: green-gray, gray-green, dark green or olivaceous, occasionally dissolving into pale green soredia in distinct spots Apothecia: at first flat, remaining so or becoming slightly convex, 0.2-0.7 mm in diam. disc: pale pink, grayish, or ±brown, often piebald, epruinose margin: distinct, level with or raised above disc, persistent, upper part pale pink to gray or brown, concolorous with disc or paler or darker, lower part paler, pale pink to gray exciple: laterally c. 60 µm wide, without crystals, ±red-brown (K+ purplish, N+ orange), fading below, darkest along the edge and in uppermost part, other parts ±colorless epithecium: ±orange-brown to red-brown in upper part (K+ purplish, N+ orange), without crystals hymenium: hyaline, 40-60 µm tall; paraphyses: c. 2 µm wide in mid-hymenium; apices: ±clavate, 2.5-5 µm wide hypothecium: colorless asci: clavate, 8-spored, Lecanora-type ascospores: hyaline, indistinctly septate or up to 7-septate, acicular, straight, curved or sigmoid, 28-58 x 1.3-2 µm Pycnidia: ±immersed in thallus, colorless, 70-150 µm in diam. conidia: filiform, curved to sigmoid, or sometimes almost straight, with 0-7 septa, 35-57 x 1.2-1.5 µm Spot tests: all negative Secondary metabolites: none detected. Habitat and ecology: on bark at the base of planted trees in a city park World distribution: Europe and western North America Sonoran distribution: known from a single locality in downtown San Diego. Notes: In Europe, Bacidina neosquamulosa is rapidly expanding in species-poor lichen communities on +eutrophicated bark in urban areas (Aptroot and van Herk 1999). The recent find in California is consistent with European ecology, and the species is reported here as new to North America. Because of nomenclatural uncertainties at the time, the species was for practical reasons described as a species of Bacidia by Aptroot and van Herk (1999). However, the species clearly belongs in Bacidina as understood here.