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

Thallus: superficial, distinct, granular to minutely squamulose, more rarely finely granular, greenish gray, forming a crust or restricted to small patches, but sometimes immersed; when squamulose often rather glossy photobiont: Stichococcus Apothecia: slender, (0.4-)1-1.9-(2.6) mm tall, 13-24 times as high as the diameter of the stalks, faintly to densely white pruinose stalk: (0.04-)0.05-1(1.2) mm in diam., black or sometimes brown, usually faintly white pruinose on the upper part capitulum: ob-conical to lenticular, (0.16-)0.19-0.34(-0.64) mm in diam. exciple: well developed, usually with faint white pruina on the lower side, formed by interwoven hyphae that extend downward towards the outer part of the stalk; hyphae +periclinally arranged in lower part, more irregularly arranged in the upper part, only slightly thicker than those of the stalk; hypothecium: pale brown, obconical with convex upper surface asci: formed in short chains from branched ascogenous hyphae with hooks, shortly cylindrical or irregular, arched or with a foot-shaped base, 11-14 x 2-2.5 µm, with uni- (to bi-)seriately arranged spores ascospores: globose, 4-5 µm in diam., smooth but with irregular, narrow cracks Anamorph: hyphomycetous conidia: one-celled, 2-3 x 1 µm Spot tests: thallus K-, C-, KC-, P- Secondary metabolites: either none detected or two unidentified substances Substrate and ecology: in dry, acid bark crevices and on wood on a wide variety of coniferous and deciduous trees, in moderately shaded and rather humid situations World distribution: widely distributed in the boreal and temperate zones of Europe, Asia, North America, and in Central and South America, Africa and Australasia Sonoran distribution: southern California. Notes: Chaenotheca trichialis is morphologically highly variable, but is characterized by the usually well developed, P-, granular to verrucose-squamulose thallus and the generally medium-sized apothecia with a faint white pruina on the exciple, and by having Stichococcus as photobiont. See also Tibell (2002).