Altitudinal distribution: subalpine belt (potential vegetation: open, taiga-like forests dominated by Larix decidua and/or Pinus cembra and Rhododendron)
Note: a species resembling Rh. reductum in the small apothecia and the eumuriform ascospores, but thallus with flat areoles, lacking lichen substances; on damp siliceous rocks, often along streams, occasionally together with R. lavatum (with larger areoles and apothecia); widespread in Europe, from the boreal to the nemoral-alpine zones, with a single record from the Eastern Alps (Austria), but the species was not recognised in earlier times, and might be more widespread in the Alps.
