LICHALP

Rhizocarpon postumum (Nyl.) Arnold

Syn.: Lecidea postuma Nyl.

Lichenised.

Substrate: siliceous rocks

Altitudinal range: from the montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies) to the alpine belt (potential vegetation: treeless Alpine grasslands and tundras, to the lower limit of perennial snow and the equilibrium line of glaciers)

Note: a species recalling Rh. distinctum in the small-sized apothecia, but medulla not amyloid and with stictic acid, apothecia less than 0.5 mm in diam. with flat, smooth discs, ascospores small (mostly less than 25 µm long) and submuriform; on siliceous rocks, often close to streams and waterfalls; widespread in Europe, but rather rare or not always distinguished, with scattered records from the Alps.