World distribution: Staurolemma omphalarioides is mainly a Mediterranean species with a western tendency (Jørgensen & Henssen 1993). The species reaches Macaronesia. North of the Mediterranen area the species is known from Norway only; the nearest sites being in former Yugoslavia and northern Italy. The remarkable disjunct distribution is discussed by Jørgensen & Henssen (1993)
Ecology: Results. The species was found on moss covered trunks of Populus tremula, and once on Sorbus aucuparia. In Namsos (3263) it grew on mature boles with a thin moss cover, associated with Collema fasciculare. Discussion. The species grows on naked bark or associated with other lichens, e.g. Degelia plumbea, Collema subflaccidum, Leptogium saturninum, Pannaria rubiginosa, Parmeliella triptophylla, Phaeophyscia orbicularis, and bryophytes like Hypnum cupressiforme, Orthotrichum speciosum, Ulota bruchii, and U. phyllantha (Degelius 1955). It may cover substantial areas where it occurs
Threats: Results. Recorded threats were Picea plantation (2). Discussion. The vegetation on the northern point of Offersøya (1182), where the lichen was particularly abundant (Degelius 1955), is today dominated by Picea plantations. The lichen flora on the few solitary Populus tremula trees observed at this site in 1993 is expected to be extinguished within few years
Status: Degelius (1955) listed 3 localities in Nærøy (1181) and Alstahaug (3264, 1182). The species were sought for in two old sites (1181, 1182), but was not found. It is not likely to occur in locality 3264, where it already in 1955 was sparse on a single tree of Sorbus aucuparia (Degelius 1955). During the investigation it was found in a new locality (3263). This site represents the only known extant occurrence in northern Europe. There are no protected localities
Specimens in other herbaria, litterature, etc.