Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life Habit: lichenized Thallus: squamulose, attached by rhizoidal web, partly with additional rhizines of longitudinally arranged hyphae squamules: dispersed or loosely aggregated, barely overlapping, adpressed or with ascending margins or ± undulate, rounded or lobed upper surface: cream or pale brown to dark brown, dull, epruinose, smooth or roughened or fissured (in one sp.) upper cortex: paraplectenchymatous, 20-50 µm thick, composed of angular cells 6-15 µm in diam., with or without an amorphous epinecral layer deriving from dead, collapsed cortical cells medulla: intricately interwoven hyphae with few to many globose cells (6-13 µm in diam.) photobiont: primary one a chlorococcoid alga, secondary photobiont absent; algal layer: c. 50-100 µm high, horizontally continuous, sharply delimited from the upper cortex, paraplectenchymatous; algal cells: 5-12 µm in diam. lower cortex: weakly differentiated or lacking, if present composed of roundish-angular cells similar to those of the medulla; rhizohyphae: hyaline or brown lower surface: pale or blackish Ascomata: perithecial, laminally immersed in the thallus, pyriform to subglobose; exciple: colorless to yellowish brown or black, 20-35 µm thick, without involucrellum; periphyses: present, interascal filaments absent; hymenial gel I+ reddish (KI+ blue) asci: clavate, thin-walled, non-amyloid, 8-spored ascospores: biseriate, simple, ellipsoid, hyaline, smooth, without halo Conidiomata: pycnidial, laminal, of Dermatocarpon-type conidia: oblong-ellipsoid to subcylindrical, subfusiform or bacilliform Secondary metabolites: none detected Geography: Europe, Japan, North and Central America Substrate: on soil and detritus. Notes: In anatomy, the genus is similar to Placidium, from which it differs by clavate asci with biseriately arranged ascospores and smaller algal cells.