World distribution: The species is widely distributed in temperate and tropical regions. According to Hale (1965), it is common all over Europe south of Scandinavia. In the British Isles the species is widespread (Purvis & James 1992c). In Fennoscandia the species is known from Norway and from southeastern Sweden where it today is regarded as extinct (Santesson 1993)
Ecology: Results. The species has been collected on trunks of Acer pseudoplatanus (5), Quercus sp. (2), Alnus glutinosa, Corylus avellana, Fagus sylvatica, and Fraxinus excelsior (all 1). One specimen was found in an oak canopy. The habitats were solitary trees in old gardens and open, often grazed woodlands in agricultural landscapes. Discussion. Punctelia subrudecta grows on the trunk of broad-leaved trees, especially Acer pseudoplatanus, in nutrient-enriched, rather open and well-lit situations. In the British Isles the species may also grow among mosses on siliceous rocks (Purvis & James 1992c)
Threats: Results. Recorded threats include building on the site (3406), wood cutting (321, 1361), spreading of liquid manure (322, 1480), air pollution, public pressure, and the abrasion of tree trunks by horses (2414). Discussion. The species is extinct in Sweden because of land development at its single site (Aronsson et al. 1995)
Status: Five of the old localities were investigated. The species was not found in any old sites, regarded as extinct in two sites, and of uncertain status in three sites. Three new localities were discovered, one with high abundance (323). There are no protected localities
Specimens in other herbaria, litterature, etc.