Physconia detersa (Nyl.) Poelt

Brundogglav

World distribution: The species is circumpolar, boreal and temperate (Poelt 1966, Thomson 1984). It is a rare species in Central Europe, known from France, Germany, Austria, Switzerland, and Ukraina (Frey 1963, Poelt 1966). Physconia detersa is rare, but widespread, in Sweden and Finland (Vitikainen 1968, Moberg 1977)

Ecology: Results. The substrate was indicated in 38 localities. It grew mainly on moss covered boulders (32), but one record was from a wall surrounding a churchyard and in some sites it was corticolous on Sorbus aucuparia (5), Alnus incana (2), and Populus tremula (1). Habitats were indicated at 28 localities of which 24 records were from various types of boreal deciduous woodlands or mixed forests which were more or less influenced by man. Two sites were churchyards, 5 sites were boulders in meadows, grazing land, or otherwise open lowland landscapes, and 1 site was an open locality in the northern boreal region. Discussion. The localities are typically situated in agricultural landscapes, in open, often grazed deciduous woodlands, where the species grows over mosses on vertical, north- to east-facing rocks. The species shows preference for calciferous (or basic), somewhat nutrient-enriched boulders. Where it is most abundant, and particularly in humid habitats, the species grows both on rocks and trees (e.g., 2417). Physconia detersa often grows together with other species of the Physciaceae, e.g. Phaeophyscia constipata, P. sciastra, Physcia caesia, P. dimidiata, Physconia enteroxantha, and P. perisidiosa. Physconia detersa seems to be less nitrophilous than P. enteroxantha, which often grows closer to dusty roads or farms. Other species that often occur at the same sites but often in somewhat more humid habitats include Cetrelia olivetorum and Heterodermia speciosa. While P. detersa is mainly a saxicolous species in Fennoscandia (Vitikainen 1968, Moberg 1977), it is mainly corticolous on deciduous trees in Central Europe (Moberg 1977). The species has a similar ecology in North America where it is found on conifers (Thomson 1984)

Threats: Results. Recorded threats were overgrowth (10), logging (9), construction (3), agricultural expansion (1), and pollution (1). Discussion. In southern Norway the main threat seems to be decreased grazing in the old grazed woodlands (resulting in overgrowth) and dense forest plantations. The species is apparently less affected by landuse changes than Cetrelia olivetorum and Heterodermia speciosa. In northern Norway, the localities along the Alta river (not investigated) may be affected by the large hydroelectric magazine

Status: Seven old localities were investigated. The species was found at 4; regarded as extinct at 1; and of uncertain status at 2. Ten new localities were discovered. No localities are protected

Specimens in other herbaria, litterature, etc.