World distribution: The species is widespread in the mesic to dry areas of the Northern Hemisphere. It occurs in Europe, Asia, Africa (Morocco), and North America (Esslinger 1977). In Europe, it occurs in Norway, Sweden, Russian Karelia, and in the mountains of central and south Europe (Austria, Switzerland, Italy, France, and Spain; Esslinger 1977, Santesson 1993). In Sweden, it occurs in Torne Lappmark (Santesson 1993)
Ecology: Results. The substrate (indicated in 9 localities) was rock (8) and soil in rock fissures (1). In two additional collections, the specimen was still attached to the rock substrate. A calcareous substrate is indicated in two localities. The habitat (indicated in 4 localities) was open rocks in a southerly exposed hillside, a south-facing rock in an open situation, a bridge, and a stone wall surrounding a churchyard. Discussion. The species is saxicolous or terricolous in rock fissures. Not much data is available on rock type, but judging from the localities, the Norwegian specimens seem to have been collected from both calciferous and siliceous rock. Both Nimis (1993) and Santesson (1993) state that it grows on siliceous rock. In Norway, the species occurs in more or less south-facing, exposed habitats. It is not restricted to the driest localities housing the 'steppe-element', although it does occur at some such sites (314, 3116). Many localities are apparently situated in old fields or traditional grazing land
Threats: Results. The two investigated localities were threatened by demolition or reconstruction of the substrate (319; a bridge), and by overgrowth by grasses and shrubs due to changes in the land use (2695). Discussion. Overgrowth by grasses and shrubs may be a threat at localities situated in agricultural landscapes (at least 314, 756, 2695, 3116, and 3117)
Status: Only 1 of the old localities was investigated; the species was found to be present. One new locality was discovered. Two localities are within nature reserves (2695, 3116)
Notes: All specimens listed below were examined by TLC. The record from Finnmark in Krog et al. (1980) and Santesson (1993) is apparently based on a specimen in O (320) which is now determined as M. disjuncta..
Specimens in other herbaria, litterature, etc.