Life habit: lichenized or lichenicolous upper surface: white, yellow, brownish yellow, gray, green or olivaceous, only occasionally with asexual reproductive structures medulla: I-, hyaline photobiont: primary one a chlorococcoid green alga (Trebouxiaceae), secondary one absent Ascomata: absent or present, apothecial, usually black, indistinct or laminal on thallus, orbicular, semi-immersed to sessile, usually dull Conidiomata: pycnidial, indistinct or laminal on thallus, immersed, with terminal conidiogenous cells conidia: hyaline, filiform Geography: cosmopolitan Substrate: soil, bryophytes, wood, bark, non-calciferous rocks, or calciferous rocks. Notes: The genus can be determined (easily) by the ascus-type, because the Lecidella-ascus is so far only known from this genus. The lichen substances are given without stating whether they are major or minor compounds or missing (for details on this subject see Knoph and Leuckert (1994, 1997 & 2000), Knoph et al. (1995). The illustration data for the species are taken from Scholz (2000) and are usually not re-checked by the authors. surface: yellowish white, rough, without soredia or isidia Apothecia: sparse or moderately abundant, orbicular, 0.7-2 mm in diam., semi-immersed to sessile, slightly constricted at base parathecium: hyaline, without crystals Pycnidia: not seen Substrate and ecology: on bark World distribution: Europe and Northern America Sonoran distribution: Arizona.