Thalli of
Pseudobogoriella species are
crustose (forming a thin crust on the
substrate), most often corticolous on bark; in the exceptional
P. striguloides the thallus is
foliicolous (on living leaves) and lies beneath the
cuticle (subcuticular), with distinct . The
sexual fruiting bodies are
perithecia—flask-shaped ascomata that open by a minute pore (the
ostiole). In most species the ostiole is apical; it is lateral in
P. lateralis. Perithecia are small, typically about 0.2–0.5 mm in diameter, and may occur solitary or aggregated. An (a dark, often thickened cap or sheath around the upper portion of the perithecium) is usually present and can be narrowly to broadly expanded at the base, sometimes forming a conspicuous fringe; this basal expansion is an important character among species. The fruit-wall () is usually unpigmented, but in
P. leuckertii it contains a red, K+ (
potassium hydroxide)-soluble pigment that dissolves in K.
Ascospores are diagnostic for the genus: they are small, one-septate (divided by a single
cross-wall), and lack thickenings. Length ranges used in the key include about 12–16
micrometres (μm), 16–22 μm, and up to 24–28 μm in the type species
P. hemisphaerica; widths are mostly 4–9 μm, with shape ratios and absolute size helping to separate similar species. A black line (a dark marginal line around the thallus) may be present and in some species is accompanied by numerous
pycnidia—minute
asexual fruiting bodies that appear as black dots—either concentrated along the prothallus (e.g.
P. punctata) or scattered over the thallus surface (e.g.
P. socialis,
P. fumosula). The combination of perithecial position and shape, involucrellum development, reaction of perithecial tissues to K, presence or absence of a black prothallus and pycnidia, and ascospore dimensions provides practical characters for identification. ==Habitat and distribution==