An easily recognizable species characterized by granules to squamules with conspicuous and relatively long hyaline hairs. These may resemble a miniature cactus. Perithecia are rarely formed, their discovery by A. Vězda enabled to decipher the genus affiliation of this interesting taxon (Vězda 1997). Until then, the species had been considered a miniature member of the *Phaeophyscia hirsuta*group.
Typical substrates are bryophytes, plant debris, soil and rocks, more or less calcareous. Rarely, the lichen may be found on tree bark. In Europe, the species occurs scattered, mostly in warmer and drier open habitat, especially in the Mediterranean and Submediterranean. However, morphologically identical types are also known from humid areas of western Europe and Africa (e.g. Scotland, Wales, Macaronesia), where it overgrows mossy trees and rocks (Orange 2013). In the Czech Republic, this lichen occurs mainly in karst areas and river valleys at lower to middle elevations. Abundant populations of A. opuntiella grow for example on slightly calcareous silicates in the canyons of some rivers, such as Vltava and Dyje.
Literature: Poelt J. (1980): Physcia opuntiella spec. nov. und die Lebensform der Sprossenden Flechten. − Flora 169: 23−31. Lisická E. & Horáková J. (1991): Physcia opuntiella Buschardt et Poelt (Flechten, Physciaceae) neu für die Tschechoslowakei. − Preslia 63: 189−191. Vězda A. (1997): Lichenes rariores exsiccati. Fasciculus tertius tricessimus (numeris 321−330). − Brno. Orange A. (2013): British and other pyrenocarpous lichens. − Cardiff: Department of Biodiversity and Systematic Biology, National Museum of Wales.taxonomic classification:
All records: 78, confirmed 69. One click on a selected square displays particular record(s), including their source(s).