Acarospora albomarginata (H. Magn.) Clauzade & Cl. Roux [nom.illeg., non B. de Lesd. nec (Herre) G. Salisb.
Syn.: Acarospora hospitans H. Magn. f. albomarginata H. Magn.
Lichenised. Poorly known taxon.
Substrate: siliceous rocks
Altitudinal range: from the montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies) to the subalpine belt (potential vegetation: open, taiga-like forests dominated by Larix decidua and/or Pinus cembra and Rhododendron)
Note: a poorly known species resembling in habitus, and probably related to A. hospitans, differing in having larger thalline squamules with a white margin, apothecia usually 2-5 per areole, surrounded by a prominent thin thalline margin and with a rough to umbonate disc, asci containing more than 100 ellipsoid ascospores (3.5-5 × 2-3 μm); on exposed outcrops and boulders of schists with low content of calcium in sunny sitations; only known from the type locality in the Eastern Alps (Switzerland).
